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[INSTALLED 2/2] Autoconf now quotes 'like this' instead of `like this'


From: Paul Eggert
Subject: [INSTALLED 2/2] Autoconf now quotes 'like this' instead of `like this'
Date: Tue, 20 Jul 2021 16:07:52 -0500

Autoconf’s diagnostics now follow current GNU coding standards,
which say that diagnostics in the C locale should quote 'like this'
with plain apostrophes instead of the older GNU style `like this'
with grave accent and apostrophe.
---
 BUGS                                      |   4 +-
 HACKING                                   |  22 +--
 Makefile.am                               |   4 +-
 NEWS                                      | 142 +++++++++---------
 README                                    |   2 +-
 README-hacking                            |   4 +-
 THANKS                                    |   2 +-
 TODO                                      |  20 +--
 bin/autoupdate.in                         |   2 +-
 configure.ac                              |   6 +-
 doc/autoconf.texi                         |  38 ++---
 lib/Autom4te/C4che.pm                     |   2 +-
 lib/Autom4te/General.pm                   |  12 +-
 lib/Autom4te/Request.pm                   |   2 +-
 lib/autoconf/autoconf.m4                  |   2 +-
 lib/autoconf/autoheader.m4                |   6 +-
 lib/autoconf/autoscan.m4                  |   2 +-
 lib/autoconf/autoupdate.m4                |   8 +-
 lib/autoconf/c.m4                         |  46 +++---
 lib/autoconf/fortran.m4                   |  24 +--
 lib/autoconf/functions.m4                 |  92 ++++++------
 lib/autoconf/general.m4                   | 170 +++++++++++-----------
 lib/autoconf/headers.m4                   |  44 +++---
 lib/autoconf/lang.m4                      |  56 +++----
 lib/autoconf/libs.m4                      |  20 +--
 lib/autoconf/programs.m4                  |  40 ++---
 lib/autoconf/specific.m4                  |  10 +-
 lib/autoconf/status.m4                    | 138 +++++++++---------
 lib/autoconf/types.m4                     | 146 +++++++++----------
 lib/autotest/general.m4                   | 110 +++++++-------
 lib/freeze.mk                             |   6 +-
 lib/m4sugar/m4sh.m4                       | 122 ++++++++--------
 lib/m4sugar/m4sugar.m4                    | 128 ++++++++--------
 tests/autotest.at                         |  14 +-
 tests/base.at                             |  10 +-
 tests/c.at                                |   6 +-
 tests/compile.at                          |  16 +-
 tests/data/ax_prog_cc_for_build_v18.m4    |   2 +-
 tests/data/gnulib_std_gnu11_2020_08_17.m4 |   6 +-
 tests/fortran.at                          |   4 +-
 tests/local.at                            |  50 +++----
 tests/m4sh.at                             |  22 +--
 tests/m4sugar.at                          |  10 +-
 tests/semantics.at                        |  30 ++--
 tests/suite.at                            |   6 +-
 tests/tools.at                            |  60 ++++----
 tests/torture.at                          |  58 ++++----
 tests/wrapper.as                          |   2 +-
 48 files changed, 866 insertions(+), 862 deletions(-)

diff --git a/BUGS b/BUGS
index 7a19bf58..cea260c2 100644
--- a/BUGS
+++ b/BUGS
@@ -11,8 +11,8 @@ file before using Autoconf, and especially git versions of 
Autoconf.
        the copyright notice and this notice are preserved.  This file is
        offered as-is, without warranty of any kind.
 
-Autoconf must not be used in production if there are ``Serious'' bugs,
-and use with caution an Autoconf with ``Important bugs''.
+Autoconf must not be used in production if there are "Serious" bugs,
+and use with caution an Autoconf with "Important bugs".
 
 * Status
 
diff --git a/HACKING b/HACKING
index e3708bc2..36932f19 100644
--- a/HACKING
+++ b/HACKING
@@ -37,7 +37,7 @@ to be written instead?).
 Make sure that a fresh checkout of Autoconf can be bootstrapped using
 the previous stable release of Autoconf.  In other words, do not use
 newly-added features in configure.ac if doing so would require an
-installed git checkout to rerun `autoreconf -i' successfully.
+installed git checkout to rerun 'autoreconf -i' successfully.
 
 * Test suite
 
@@ -48,12 +48,12 @@ Use liberally.
 Try to run the test suite with more severe conditions before a
 release:
 
-- Run `make syntax-check'
+- Run 'make syntax-check'
   This makes sure that the source files follow some consistent rules.
   The checks live in maint.mk, shared from gnulib, and customized in
   cfg.mk.
 
-- Run `make distcheck' and `make maintainer-check'.
+- Run 'make distcheck' and 'make maintainer-check'.
 
 - Try some real world packages
   A good example is the coreutils package.
@@ -96,28 +96,28 @@ hints on the testsuite.  If needed, update cfg.mk with 
details
 specific to your environment, such as the location of a gnulib checkout.
 
 ** Update the foreign files
-Running `make fetch' in the top level should grab it all for you; you
+Running 'make fetch' in the top level should grab it all for you; you
 should check the results before committing them in git.
 
 ** Set the version number
 Update the version number in NEWS (with version, date, and release
-type).  Make sure all changes are committed, then run `git tag -s -m
+type).  Make sure all changes are committed, then run 'git tag -s -m
 <version> -u <gpg_key> v<version>'.  Do not push anything upstream at
 this point.
 
 ** Update configure
 As much as possible, make sure to release an Autoconf that uses
 itself.  That's easy: just be in the top level, and run
-`tests/autoconf'.  Or install this autoconf and run `autoreconf -f'.
+'tests/autoconf'.  Or install this autoconf and run 'autoreconf -f'.
 
 ** Make the release
-Run `make {alpha,beta,stable}' depending on which type of release this
+Run 'make {alpha,beta,stable}' depending on which type of release this
 is.  This runs the various checks, creates delta files, creates a
 preliminary announcement in ~/announce-autoconf-<version>, prints
 out the command to upload the files, and updates the previous version
 file.
 
-If it fails, run `git tag -d v<version>', fix the problems, and go
+If it fails, run 'git tag -d v<version>', fix the problems, and go
 back to the step of setting the version.
 
 ** Upload
@@ -127,7 +127,7 @@ that the files are correctly uploaded before sending a 
release
 announcement.
 
 ** Push the updates
-Run `git push origin refs/tags/v<version>' to push the release tag.
+Run 'git push origin refs/tags/v<version>' to push the release tag.
 
 ** Announce
 Complete/fix the announcement file, and email it at least to
@@ -139,9 +139,9 @@ also mail to platform-testers@gnu.org.
 For alpha and beta releases, the process is complete.  For stable
 releases, there are several other web pages that need updates.
 
-Update the online manual: Run `make web-manual', then copy the
+Update the online manual: Run 'make web-manual', then copy the
 contents of doc/manual into a CVS checkout of the documentation
-repository.  Remember to use `cvs add -ko' so that RCS keywords in the
+repository.  Remember to use 'cvs add -ko' so that RCS keywords in the
 generated output do not get expanded improperly.
   $ export CVS_RSH=ssh
   $ cvs -z3 -d:ext:<user>@cvs.sv.gnu.org:/web/autoconf co autoconf
diff --git a/Makefile.am b/Makefile.am
index 17e1f8f4..2ea1dc15 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -70,15 +70,13 @@ MAINTAINERCLEANFILES += $(srcdir)/INSTALL
 
 # Don't leave blank line at end of file.
 OMIT_TRAILING_EMPTY_LINES = '/^$$/H; /^$$/d; x; s/\n//p; s/\n*//; x'
-# Prefer 'plain quotes' over `makeinfo quotes'.
-CONVERT_QUOTES = "s/\`\([^']*\)'/'\1'/g"
 
 $(srcdir)/INSTALL: $(top_srcdir)/doc/install.texi
        echo @firstparagraphindent insert                               \
          | cat - $(top_srcdir)/doc/install.texi > tmp.texi
        $(MAKEINFO) $(custom_MAKEINFOFLAGS) $(MAKEINFOFLAGS)            \
             --plaintext tmp.texi                                       \
-         | sed -e $(CONVERT_QUOTES) -e $(OMIT_TRAILING_EMPTY_LINES)    \
+         | sed -e $(OMIT_TRAILING_EMPTY_LINES)                         \
             > $@-t && mv $@-t $@
        rm -f tmp.texi
 endif
diff --git a/NEWS b/NEWS
index 8b4f9d64..3c50ff8a 100644
--- a/NEWS
+++ b/NEWS
@@ -5,6 +5,14 @@ GNU Autoconf NEWS - User visible changes.
 ** Backward incompatibilities
 ** New features
 ** Obsolete features and new warnings
+
+*** Autoconf now quotes 'like this' instead of `like this'.
+
+  Autoconf’s diagnostics now follow current GNU coding standards,
+  which say that diagnostics in the C locale should quote 'like this'
+  with plain apostrophes instead of the older GNU style `like this'
+  with grave accent and apostrophe.
+
 ** Notable bug fixes
 
 * Noteworthy changes in release 2.71 (2021-01-28) [stable]
@@ -544,7 +552,7 @@ GNU Autoconf NEWS - User visible changes.
   Released by Eric Blake, based on git versions 2.67.*.
 
 ** AC_MSG_ERROR (and AS_ERROR) can once again be followed immediately by
-   `dnl'.  Regression introduced in 2.66.
+   'dnl'.  Regression introduced in 2.66.
 
 ** AC_INIT again allows URLs with '?' for its BUG-REPORT argument.
    Regression introduced in 2.66.
@@ -626,7 +634,7 @@ GNU Autoconf NEWS - User visible changes.
 ** The macros AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, and
    AC_TYPE_INT64_T work again.  Regression introduced in 2.65.
 
-** AC_PROG_INSTALL correctly uses `shtool' again.  Regression introduced
+** AC_PROG_INSTALL correctly uses 'shtool' again.  Regression introduced
    in 2.64.
 
 ** Autoconf should work on EBCDIC hosts.
@@ -639,8 +647,8 @@ GNU Autoconf NEWS - User visible changes.
 ** Autotest testsuites accept an option --recheck to rerun tests that
    failed or passed unexpectedly during the last non-debug testsuite run.
 
-** AC_ARG_ENABLE and AC_ARG_WITH now also accept `+' signs in `--enable-*'
-   and `--with-*' arguments, converting them to underscores for the variable
+** AC_ARG_ENABLE and AC_ARG_WITH now also accept '+' signs in '--enable-*'
+   and '--with-*' arguments, converting them to underscores for the variable
    names.
 
 ** In configure scripts, loading CONFIG_SITE no longer searches PATH,
@@ -712,7 +720,7 @@ GNU Autoconf NEWS - User visible changes.
    this gives the intuitive behavior of "[b c]" in the output (2.63
    gave the output of "[b], [c]", and 2.64 encountered a failure).
 
-** The `$tmp' temporary directory used in config.status is documented for
+** The '$tmp' temporary directory used in config.status is documented for
    public use now.
 
 ** config.status now provides a --config option to produce the configuration.
@@ -799,7 +807,7 @@ GNU Autoconf NEWS - User visible changes.
 
 ** AC_INIT now takes an optional fifth parameter that can be used to
    set AC_PACKAGE_URL, a URL for the package's home page; the URL is
-   used in `configure --help' and is also available via AC_DEFINE.
+   used in 'configure --help' and is also available via AC_DEFINE.
 
 ** Autotest testsuites accept an option --jobs[=N] for parallel testing.
    This feature is still in testing, and may not work on every
@@ -817,7 +825,7 @@ GNU Autoconf NEWS - User visible changes.
    providing a fourth parameter to AC_CHECK_HEADER/AC_CHECK_HEADERS.
 
 ** Autoreconf added aclocal to the set of programs affected by the
-   `autoreconf -I dir' option.
+   'autoreconf -I dir' option.
 
 ** The following documented m4sugar macros are new:
    m4_chomp  m4_chomp_all  m4_cleardivert  m4_curry  m4_default_quoted
@@ -836,7 +844,7 @@ GNU Autoconf NEWS - User visible changes.
    internally in more places, such as AC_DEFINE and AT_CHECK.  Most
    uses of AC_DEFINE and AT_CHECK should not behave any differently;
    however, it may be necessary to add double-quoting around
-   unbalanced `(' where single-quoting used to be sufficient.
+   unbalanced '(' where single-quoting used to be sufficient.
 
 ** The following documented m4sh macros are new:
    AS_INIT_GENERATED  AS_LINENO_PREPARE  AS_ME_PREPARE  AS_SET_STATUS
@@ -917,7 +925,7 @@ GNU Autoconf NEWS - User visible changes.
    AT_KEYWORDS([m4_if([$1], [], [default])]) no longer complains about
    the possibly unexpanded m4_if [regression introduced in 2.62].
 
-** Config header templates `#undef UNDEFINED /* comment */' do not lead to
+** Config header templates '#undef UNDEFINED /* comment */' do not lead to
    nested comments any more; regression introduced in 2.62.
 
 
@@ -935,7 +943,7 @@ GNU Autoconf NEWS - User visible changes.
      Further, for config headers, the total size of values is not limited by
      the POSIX length limit of text lines any more, only each single line.
 
-** New config variable `top_build_prefix'.
+** New config variable 'top_build_prefix'.
 
 ** New Autoconf macros:
    AC_AUTOCONF_VERSION  AC_OPENMP  AC_PATH_PROGS_FEATURE_CHECK
@@ -989,7 +997,7 @@ GNU Autoconf NEWS - User visible changes.
    command './configure --prefix=/usr/' will still result in an
    expanded libdir value of /usr/lib, not /usr//lib.
 
-** `configure --help=recursive' now works in read-only trees and from
+** 'configure --help=recursive' now works in read-only trees and from
    unconfigured build trees.
 
 ** If precious variables differ only in whitespace, then the cache consistency
@@ -1097,9 +1105,9 @@ GNU Autoconf NEWS - User visible changes.
    The documentation now favors the use of M4sugar macros m4_warn and
    m4_fatal, since the naming makes it more obvious that the
    diagnostics are associated with M4 expansion (ie. when running
-   `autoconf'), and offers less confusion with the AC_MSG_ERROR,
+   'autoconf'), and offers less confusion with the AC_MSG_ERROR,
    AC_MSG_FAILURE, and AC_MSG_WARN macros which manage diagnostics
-   when running `configure'.  We have no current plans to remove these
+   when running 'configure'.  We have no current plans to remove these
    macros.
 
 
@@ -1129,7 +1137,7 @@ GNU Autoconf NEWS - User visible changes.
 ** Many uses of 'echo' have been rewritten so that Autoconf-generated
    scripts have fewer problems with strings or file names containing
    embedded special characters such as backslash or leading "-".  This
-   was implemented by using `printf '%s\n' "$foo"' instead of `echo
+   was implemented by using 'printf '%s\n' "$foo"' instead of 'echo
    "$foo"' when printf works.  Due to the implementation technique
    used, Autoconf-generated scripts now run considerably more slowly
    on ancient implementations lacking printf.  However, this should
@@ -1218,7 +1226,7 @@ GNU Autoconf NEWS - User visible changes.
   GNU make keeps the installation instructions simpler.
 
 ** Even more safety checks for the new Directory variables:
-  Warn about suspicious `${datarootdir}' found in config files output.
+  Warn about suspicious '${datarootdir}' found in config files output.
 
 ** AC_TRY_COMMAND, AC_TRY_EVAL, ac_config_guess, ac_config_sub, ac_configure
   These never-documented macros and variables have been marked with
@@ -1264,7 +1272,7 @@ GNU Autoconf NEWS - User visible changes.
 
 ** autoreconf
   For compatibility with future Libtool 2.0, autoreconf will invoke
-  libtoolize with the option `--ltdl' now, if LT_CONFIG_LTDL_DIR is
+  libtoolize with the option '--ltdl' now, if LT_CONFIG_LTDL_DIR is
   used.
 
 * Major changes in Autoconf 2.59c
@@ -1294,11 +1302,11 @@ GNU Autoconf NEWS - User visible changes.
     infodir       info documentation [DATAROOTDIR/info]
     mandir        man documentation [DATAROOTDIR/man]
 
-  This means that if you use any of `@datadir@', `@infodir@', or
-  `@mandir@' in a file, you will have to ensure `${datarootdir}' is
+  This means that if you use any of '@datadir@', '@infodir@', or
+  '@mandir@' in a file, you will have to ensure '${datarootdir}' is
   defined in this file.  As a temporary measure, if any of those are
-  found but no mention of `datarootdir', the substitutions will be
-  replaced with values that do not contain `${datarootdir}', and a
+  found but no mention of 'datarootdir', the substitutions will be
+  replaced with values that do not contain '${datarootdir}', and a
   warning will be issued.
 
 ** @top_builddir@ is now a dir name: it is always nonempty and doesn't have
@@ -1324,7 +1332,7 @@ GNU Autoconf NEWS - User visible changes.
   X11/Intrinsic.h and XtMalloc (Xt).
 
 ** AC_PRESERVE_HELP_ORDER
-  New macro that causes `configure' to display help strings for AC_ARG_ENABLE
+  New macro that causes 'configure' to display help strings for AC_ARG_ENABLE
   and AC_ARG_WITH arguments in one region, in the order defined.  The default
   behavior is to group options of each classes separately.
 
@@ -1384,9 +1392,9 @@ GNU Autoconf NEWS - User visible changes.
   New macro for copyright notices in testsuite files.
 
 ** ALLOCA, LIBOBJS, LTLIBOBJS
-  Object names added to these variables are now prefixed with `${LIBOBJDIR}',
-  as in `${LIBOBJDIR}alloca.o'.  LIBOBJDIR is meant to be defined from
-  `Makefile.in' in case the object files lie in a different directory.
+  Object names added to these variables are now prefixed with '${LIBOBJDIR}',
+  as in '${LIBOBJDIR}alloca.o'.  LIBOBJDIR is meant to be defined from
+  'Makefile.in' in case the object files lie in a different directory.
   The LIBOBJDIR feature is experimental.
 
 ** autoreconf
@@ -1570,7 +1578,7 @@ Release tips:
 - Supports -W/--warnings.
 
 - -m/--make
-  Once the GNU Build System reinstalled, run `./config.status
+  Once the GNU Build System reinstalled, run './config.status
   --recheck && ./config.status && make' if possible.
 
 ** autom4te
@@ -1578,7 +1586,7 @@ Release tips:
 - Supports --cache, and --no-cache.
 
 - ~/.autom4te.cfg makes it possible to disable the caching mechanism
-  (autom4te.cache).  See `Customizing autom4te' in the documentation.
+  (autom4te.cache).  See 'Customizing autom4te' in the documentation.
 
 ** config.status
   Supports --quiet.
@@ -1616,7 +1624,7 @@ Release tips:
   produce more \ than wanted.
 
   Please, note that in the future the same problem will happen with
-  AC_MSG_*: use `autoreconf -f -Wall'.
+  AC_MSG_*: use 'autoreconf -f -Wall'.
 
 ** Bug Fixes
 
@@ -1645,7 +1653,7 @@ Release tips:
 - ./configure <host>
 
   The compatibility hooks with the old scheme will be completely
-  removed.  Please, advice/use `--build', `--host', and `--target'
+  removed.  Please, advice/use '--build', '--host', and '--target'
   only.
 
 - AC_CHECK_HEADER, AC_CHECK_HEADERS
@@ -1666,7 +1674,7 @@ Release tips:
   Special characters in AC_MSG_* need not be quoted.  Currently,
   Autoconf has heuristics to decide when a string is escaped, or has
   to be escaped.  This scheme is fragile, and will be removed; the
-  only risk is uglified messages.  Please, run `autoreconf -f -Wall'
+  only risk is uglified messages.  Please, run 'autoreconf -f -Wall'
   to find occurrences that will be affected.
 
 * Major changes in Autoconf 2.54
@@ -1701,7 +1709,7 @@ Release tips:
        # built via the ANSI2KNR-filtering rules.
        LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
 
-  and read the `AC_LIBOBJ vs LIBOBJS' section.  Do not define U in
+  and read the 'AC_LIBOBJ vs LIBOBJS' section.  Do not define U in
   your Makefiles either.
 
 - AC_CONFIG_LINKS now makes copies if it can't make links.
@@ -1726,12 +1734,12 @@ Release tips:
   looks for getloadavg.c in the CONFIG_LIBOBJ_DIR.
 
 - AC_FUNC_MALLOC
-  Now defines HAVE_MALLOC to 0 if `malloc' does not work, and asks
+  Now defines HAVE_MALLOC to 0 if 'malloc' does not work, and asks
   for an AC_LIBOBJ replacement.
 
 ** Bug fixes
 
-- Spurious complaints from `m4_bmatch' about invalid regular
+- Spurious complaints from 'm4_bmatch' about invalid regular
   expressions are suppressed.
 
 - Empty top_builddirs are properly handled.
@@ -1786,13 +1794,13 @@ Release tips:
   AC_TRY_CPP, AC_TRY_COMPILE, AC_TRY_LINK and AC_TRY_RUN.
 - Licensing
   The Autoconf manual is now distributed under the terms of the GNU FDL.
-- Section `Hosts and Cross-Compilation'
+- Section 'Hosts and Cross-Compilation'
   Explains the rationale for the 2.5x changes in the cross-compilation
   chain, and in the relationships between build, host, and target
   types.
-  Emphasizes that `cross-compilation' == `--host is given'.
+  Emphasizes that 'cross-compilation' == '--host is given'.
   If you are working on compilers etc., be sure to read this section.
-- Section `AC_LIBOBJ vs. LIBOBJS'
+- Section 'AC_LIBOBJ vs. LIBOBJS'
   Explains why assigning LIBOBJS directly is now an error.
   Details how to update the code.
 
@@ -1800,7 +1808,7 @@ Release tips:
 
 - $LINENO
   Now used instead of hard coded line numbers.
-  This eases the comparison of `configure's, and diminishes the
+  This eases the comparison of 'configure's, and diminishes the
   pressure over control version archives.
   Automatic replacement for shells that don't support this feature.
 - New output variables
@@ -1828,9 +1836,9 @@ Release tips:
 - autoreconf
   --m4dir is no longer supported.
 - autoreconf
-  Now runs only in the specified directories, defaulting to `.',
+  Now runs only in the specified directories, defaulting to '.',
   but understands AC_CONFIG_SUBDIRS for dependent directories.
-  Before, it used to run on all the `configure.ac' found in the
+  Before, it used to run on all the 'configure.ac' found in the
   current tree.
   Independent packages are properly updated.
 
@@ -1855,8 +1863,8 @@ Release tips:
   ACTION-IF-UNKNOWN arguments.  All are optional, and the default
   for ACTION-IF-TRUE is to define WORDS_BIGENDIAN like AC_C_BIGENDIAN
   always did.
-- AC_C_LONG_DOUBLE now succeeds only if `long double' has more range or
-  precision than `double'.
+- AC_C_LONG_DOUBLE now succeeds only if 'long double' has more range or
+  precision than 'double'.
 
 ** Generic macros
 
@@ -1897,7 +1905,7 @@ Release tips:
 - AC_ARG_VAR
 - Quadrigraphs
   This feature was present in autoconf 2.50 but was not documented.
-  For example, `@<:@' is translated to `[' just before output.  This
+  For example, '@<:@' is translated to '[' just before output.  This
   is useful when writing strings that contain unbalanced quotes, or
   other hard-to-quote constructs.
 - m4_pattern_forbid, m4_pattern_allow
@@ -1922,7 +1930,7 @@ Release tips:
 - Using --program-suffix/--program-prefix is portable.
 - Failures to detect the default compiler's output extension are less
   likely.
-- `config.status foo' works properly when `foo' depends on variables
+- 'config.status foo' works properly when 'foo' depends on variables
   set in an AC_CONFIG_THING INIT-CMD.
 - autoheader is more robust to broken input.
 - Fixed Fortran name-mangling and link tests on a number of systems,
@@ -1936,15 +1944,15 @@ Release tips:
 - AC_ARG_VAR refuses to run configure when precious variables have
   changed.
 - Versions of compilers are dumped in the logs.
-- AC_CHECK_TYPE recognizes use of `foo_t' as a replacement type.
+- AC_CHECK_TYPE recognizes use of 'foo_t' as a replacement type.
 
 ** Specific Macros
 - AC_PATH_XTRA only adds -ldnet to $LIBS if it's needed to link.
 - AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS are obsoleted.
 - AM_FUNC_ERROR_AT_LINE, AM_FUNC_FNMATCH, AM_FUNC_MKTIME,
   AM_FUNC_OBSTACK, and AM_FUNC_STRTOD are now activated.
-  Be sure to read `Upgrading from Version 2.13' to understand why
-  running `autoupdate' is needed.
+  Be sure to read 'Upgrading from Version 2.13' to understand why
+  running 'autoupdate' is needed.
 - AC_F77_DUMMY_MAIN, AC_F77_MAIN: new macros to detect whether
   a main-like routine is required/possible when linking C/C++ with
   Fortran.  Users of e.g. AC_F77_WRAPPERS should be aware of these.
@@ -1979,7 +1987,7 @@ config.guess, config.sub.
 ** autoconf
 - --trace
   Provides a safe and powerful means to trace the macro uses.  This
-  provide the parsing layer for tools which need to `study'
+  provide the parsing layer for tools which need to 'study'
   configure.in.
 
 - --warnings
@@ -2000,11 +2008,11 @@ which might be needed to move from an old macro to its 
newer
 equivalent.
 
 You are strongly encouraged to use it to modernize both your
-`configure.in' and your .m4 extension files.
+'configure.in' and your .m4 extension files.
 
 ** autoheader
 The internal machinery of autoheader has completely changed.  As a
-result, using `acconfig.h' should be considered to be obsoleted, and
+result, using 'acconfig.h' should be considered to be obsoleted, and
 you are encouraged to get rid of it using the AH macros.
 
 ** autoreconf
@@ -2044,18 +2052,18 @@ test cases in this new framework.
   to $host.
   Cross-compilation is a global status of the package, it no longer
   depends upon the current language.
-  Cross compilation is enabled iff the user specified `--host'.
-  `configure' now fails if it can't run the executables it compiles,
+  Cross compilation is enabled iff the user specified '--host'.
+  'configure' now fails if it can't run the executables it compiles,
   unless cross-compilation is enabled.
 - Cache file
   The cache file is disabled by default.  The new options
-  `--config-cache', `-C' set the cache to `config.cache'.
+  '--config-cache', '-C' set the cache to 'config.cache'.
 
 ** config.status
 - faster
   Much faster on most architectures.
 - concurrent executions
-  It is safe to use `make -j' with config.status.
+  It is safe to use 'make -j' with config.status.
 - human interface improved
   It is possible to invoke
     ./config.status foobar
@@ -2079,7 +2087,7 @@ test cases in this new framework.
 
 ** General changes.
 - Uniform quotation
-  Most macros, if not all, now strictly follow the `one quotation
+  Most macros, if not all, now strictly follow the 'one quotation
   level' rule.  This results in a more predictable expansion.
 
 - AC_REQUIRE
@@ -2091,7 +2099,7 @@ test cases in this new framework.
   Document and ask for the registration of an envvar.
 
 - AC_CONFIG_SRCDIR
-  Specifies the file which `configure' should look for when trying to
+  Specifies the file which 'configure' should look for when trying to
   find the source tree (used to be handled by AC_INIT).
 
 - AC_CONFIG_COMMANDS
@@ -2117,7 +2125,7 @@ test cases in this new framework.
 
 - AC_HELP_STRING
   To format an Autoconf macro's help string so that it looks pretty
-  when the user executes `configure --help'.
+  when the user executes 'configure --help'.
 
 
 ** Generic Test Macros
@@ -2173,10 +2181,10 @@ test cases in this new framework.
   Sets GETGROUPS_LIBS.
 
 - AC_FUNC_GETLOADAVG
-  Defines `HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of `NLIST_NAME_UNION'.
+  Defines 'HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of 'NLIST_NAME_UNION'.
 
 - AC_PROG_LEX
-  Now integrates `AC_DECL_YYTEXT' which is obsoleted.
+  Now integrates 'AC_DECL_YYTEXT' which is obsoleted.
 
 - AC_SYS_LARGEFILE
   Arrange for large-file support.
@@ -2197,7 +2205,7 @@ Major changes in Autoconf 2.13:
 
 * Support for building on 32-bit Windows systems where the only available C or
   C++ compiler is the Microsoft Visual C++ command line compiler
-  (`cl').  Additional support for building on 32-bit Windows systems which are
+  ('cl').  Additional support for building on 32-bit Windows systems which are
   using the Cygwin or Mingw32 environments.
 * Support for alternative object file and executable file extensions.
   On 32-bit Windows, for example, these are .obj and .exe. These are discovered
@@ -2213,7 +2221,7 @@ Major changes in Autoconf 2.13:
   causing failures on systems using recent versions of the EGCS C++
   compiler.
 * Fixed an important bug in AC_CHECK_TYPE that would cause a configure
-  script to report that `sometype_t' was present when only `type_t'
+  script to report that 'sometype_t' was present when only 'type_t'
   was defined.
 * Merge of the FSF version of config.guess and config.sub to modernize
   these scripts. Add support for a few new hosts in config.guess.
@@ -2243,7 +2251,7 @@ Major changes in Autoconf 2.11:
 
 * AC_PROG_CC and AC_PROG_CXX check whether the compiler works.
   They also default CFLAGS/CXXFLAGS to "-g -O2" for gcc, instead of "-g -O".
-* AC_REPLACE_FUNCS defines HAVE_foo if the system has the function `foo'.
+* AC_REPLACE_FUNCS defines HAVE_foo if the system has the function 'foo'.
 * AC_CONFIG_HEADERS expands shell variables in its argument.
 * New macros: AC_FUNC_FNMATCH, AC_FUNC_SETPGRP.
 * The "checking..." messages and the source code for test programs that
@@ -2257,7 +2265,7 @@ Major changes in Autoconf 2.10:
   Released May 7th, 1996, by Roland McGrath
 
 * Bug fixes.
-* The cache variable names used by `AC_CHECK_LIB(LIB, FUNC, ...)' has
+* The cache variable names used by 'AC_CHECK_LIB(LIB, FUNC, ...)' has
   changed: now $ac_cv_lib_LIB_FUNC, previously $ac_cv_lib_LIB.
 
 Major changes in Autoconf 2.9:
@@ -2511,7 +2519,7 @@ Major changes in Autoconf 1.8:
 * autoheader optionally copies config.h.top to the beginning of config.h.in.
 * The example Makefile dependencies for configure et al. work better.
 * Namespace cleanup: all shell variables used internally by Autoconf
-  have names beginning with `ac_'.
+  have names beginning with 'ac_'.
 
 More big improvements are in process for future releases, but have not
 yet been (variously) finished, integrated, tested, or documented enough
@@ -2553,7 +2561,7 @@ Major changes in Autoconf 1.4:
   name of the M4 program to use.
 * The --macrodir option to autoconf and autoheader specifies the directory
   in which acspecific.m4, acgeneral.m4, etc. reside if not the default.
-* autoconf and autoheader can take `-' as their file names, which means to
+* autoconf and autoheader can take '-' as their file names, which means to
   read stdin as input.
 * Resulting configure scripts can take a --verbose option which causes them
   to print the results of their tests.
@@ -2562,11 +2570,11 @@ Major changes in Autoconf 1.4:
   expansion done by the shell.  If you don't want this, use
   AC_DEFINE_UNQUOTED instead.
 * Much textual processing done with external calls to tr and sed have been
-  internalized with builtin M4 `patsubst' and `translit' calls.
+  internalized with builtin M4 'patsubst' and 'translit' calls.
 * AC_OUTPUT doesn't hardwire the file names it outputs.  Instead, you can
-  set the shell variables `gen_files' and `gen_config' to the list of
+  set the shell variables 'gen_files' and 'gen_config' to the list of
   file names to output.
-* AC_DECLARE_YYTEXT does an AC_SUBST of `LEX_OUTPUT_ROOT', which may be
+* AC_DECLARE_YYTEXT does an AC_SUBST of 'LEX_OUTPUT_ROOT', which may be
   "lex.yy" or "lexyy", depending on the system.
 * AC_PROGRAMS_CHECK takes an optional third arg.  If given, it is used as
   the default value.
@@ -2578,7 +2586,7 @@ Major changes in Autoconf 1.3:
 
 configure no longer requires awk for packages that use a config.h.
 Support handling --with-PACKAGE options.
-New `autoheader' script to create `config.h.in' from `configure.in'.
+New 'autoheader' script to create 'config.h.in' from 'configure.in'.
 Ignore troublesome -lucb and -lPW when searching for alloca.
 Rename --exec_prefix to --exec-prefix for GNU standards conformance.
 Improve detection of STDC library.
diff --git a/README b/README
index 2cedb951..67958457 100644
--- a/README
+++ b/README
@@ -35,7 +35,7 @@ Mail suggestions to autoconf@gnu.org, report bugs to
 bug-autoconf@gnu.org, and submit patches to autoconf-patches@gnu.org.
 All changes can be tracked at the read-only autoconf-commit@gnu.org.
 Always include the Autoconf version number, which you can get by
-running `autoconf --version'.  Archives of bug-autoconf@gnu.org can be
+running 'autoconf --version'.  Archives of bug-autoconf@gnu.org can be
 found in <https://lists.gnu.org/archive/html/bug-autoconf/>, and
 similarly for the other mailing lists.
 
diff --git a/README-hacking b/README-hacking
index 1743dd37..31d043c1 100644
--- a/README-hacking
+++ b/README-hacking
@@ -45,11 +45,11 @@ then add the following to .git/config or ~/.gitconfig:
        funcname = ^@node[\t ][\t ]*\\([^,][^,]*\\)
 
 Only building the initial full source tree will be a bit painful.
-Later, a plain `git pull && make' should be sufficient.
+Later, a plain 'git pull && make' should be sufficient.
 
 If you want to test Autoconf on a machine without git, it may be
 easier to first bootstrap Autoconf on a different machine with git,
-run `make dist', and copy the tarball to the machine under test.  It
+run 'make dist', and copy the tarball to the machine under test.  It
 should always be possible to create a self-contained tarball which
 does not rely on the bootstrap-only tools.
 
diff --git a/THANKS b/THANKS
index 4d3531c7..6ebe7dbd 100644
--- a/THANKS
+++ b/THANKS
@@ -391,7 +391,7 @@ Simon Josefsson             jas@extundo.com
 Simon Leinen                simon@lia.di.epfl.ch
 Slava Sysoltsev             Viatcheslav.Sysoltsev@h-d-gmbh.de
 Stefan Seefeld              stefan@codesourcery.com
-Stefan `Sec' Zehl           ?
+Stefan 'Sec' Zehl           ?
 Stefano Lattarini           stefano.lattarini@gmail.com
 Stepan Kasal                kasal@ucw.cz
 Stéphane Chazelas           Stephane_Chazelas@yahoo.fr
diff --git a/TODO b/TODO
index 2359f8ea..2923974c 100644
--- a/TODO
+++ b/TODO
@@ -14,7 +14,7 @@ and the like, don't have a consistent way to handle multi-line
 arguments.  Fix, test, and document.
 
 ** --target & AC_ARG_PROGRAM
-Shouldn't *any* `program' be installed as `$target_alias-program' even
+Shouldn't *any* 'program' be installed as '$target_alias-program' even
 if AC_ARG_PROGRAM is not called?  That would be much more predictable.
 Ian?
 
@@ -161,8 +161,8 @@ autoupdate do its job on old configure.ac.
 * Even later
 
 ** Pentateuch
-Heck, there is nothing after `Deuteronomy'!  We're stuck, but we
-_must_ update the `history' section.  Can't go to `New testament', we
+Heck, there is nothing after 'Deuteronomy'!  We're stuck, but we
+_must_ update the 'history' section.  Can't go to 'New testament', we
 might hurt feelings?  In addition, it means that the Messiah has come,
 which might be slightly presumptuous :).  Still, someone fluent in
 English should write it.
@@ -176,8 +176,8 @@ Hi Robert,
 
 > The documentation says that AC_PATH_XTRA
 >      ... adds the C compiler flags that X needs to output variable
->      `X_CFLAGS', and the X linker flags to `X_LIBS'.  If X is not
->      available, adds `-DX_DISPLAY_MISSING' to `X_CFLAGS'.
+>      'X_CFLAGS', and the X linker flags to 'X_LIBS'.  If X is not
+>      available, adds '-DX_DISPLAY_MISSING' to 'X_CFLAGS'.
 
 > It doesn't seem to add -DX_DISPLAY_MISSING to X_CFLAGS.  X_DISPLAY_MISSING
 > ends up defined in config.h, instead.
@@ -192,7 +192,7 @@ But you are right--the documentation is not clear about 
this.  I'll change
 it.
 
 > In fact it looks to me as if right now, X_CFLAGS is used only for
-> specifying directories where X include files are stored, via the `-I' option.
+> specifying directories where X include files are stored, via the '-I' option.
 > Maybe it should really be called X_CPPFLAGS?
 
 Well, perhaps.  If you feel strongly about this, feel free to submit a
@@ -223,7 +223,7 @@ the doc easier to update when people add/change macros.  
The name
 The error messages for indir and dumpdef are uselessly different.  Fix
 this for translators.
 
-** Tracing `builtin'
+** Tracing 'builtin'
 F**k!  --trace FOO does not catch indir([FOO], $@)!
 Fixed in M4 1.6, but we can't rely on it yet.
 
@@ -287,7 +287,7 @@ should generate all the templates.
 ** Specializing loops.
 For instance, make AC_CHECK_FUNC[S] automatically use any particular
 macros for the listed functions.
-This requires to obsolete the feature `break' in ACTION-IF, since all
+This requires to obsolete the feature 'break' in ACTION-IF, since all
 the loops are to be handled by m4, not sh.
 
 ** Faces of a test
@@ -296,7 +296,7 @@ configure snippet (AC_foo), a config.h snippet (AH_foo), a 
system.h
 snippet (AS_foo), documentation (AD_foo) and, why not, the some C code
 for instance to replace a function.
 
-The motivation for the `faces' is to encapsulate.  It is abnormal that
+The motivation for the 'faces' is to encapsulate.  It is abnormal that
 once one has a configure macro, then she has to read somewhere to find
 the piece of system.h to use etc.  The macros should come in a
 self-contained way, or, said it another way, PnP.
@@ -453,7 +453,7 @@ It also occurs with a bunch more libposix4 functions that 
most people
 probably aren't worried about yet, e.g. shm_open.
 
 All these functions fail with errno set to ENOSYS (89)
-``Operation not applicable''.
+"Operation not applicable".
 
 Perhaps Autoconf should have a specific macro for fnmatch, another for
 glob+globfree, another for regcomp+regexec+regerror+regfree, and
diff --git a/bin/autoupdate.in b/bin/autoupdate.in
index c86203a4..b5804880 100644
--- a/bin/autoupdate.in
+++ b/bin/autoupdate.in
@@ -882,7 +882,7 @@ exit 0;
 #     NEW([0, 0],
 #        0)
 #
-# And we just run m4 on it.  Et voila`, Monsieur !  Mais oui, mais oui.
+# And we just run m4 on it.  Et voilà, Monsieur !  Mais oui, mais oui.
 #
 # Well, there are a few additional technicalities.  For instance, we
 # rely on 'changequote', 'ifelse' and 'defn', but we don't want to
diff --git a/configure.ac b/configure.ac
index e6750473..e3e32d1c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -17,11 +17,9 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-AC_PREREQ([2.62])
+AC_PREREQ([2.69])
 
-AC_INIT([GNU Autoconf],
-       m4_esyscmd([build-aux/git-version-gen .tarball-version]),
-       [bug-autoconf@gnu.org])
+AC_INIT([GNU Autoconf],[m4_esyscmd(build-aux/git-version-gen 
.tarball-version)],[bug-autoconf@gnu.org])
 AC_CONFIG_SRCDIR([lib/autoconf/autoconf.m4])
 
 AC_CONFIG_AUX_DIR([build-aux])
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 965d6502..9f632ced 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -182,9 +182,9 @@
 @end macro
 @end ifclear
 
-@c Define an index for functions: `alloca' etc.  Used for the
-@c portability sections and so on.  We can't use `fn' (aka `fnindex),
-@c since `@defmac' goes into it => we'd get all the macros too.
+@c Define an index for functions: 'alloca' etc.  Used for the
+@c portability sections and so on.  We can't use 'fn' (aka 'fnindex'),
+@c since '@defmac' goes into it => we'd get all the macros too.
 
 @c   FIXME: Aaarg!  It seems there are too many indices for TeX :(
 @c
@@ -17107,7 +17107,7 @@ not exhaustive, but you should be safe if you avoid the 
name
 @code{status} and names containing only upper-case letters and
 underscores.
 
-@c Alphabetical order, case insensitive, `A' before `a'.
+@c Alphabetical order, case insensitive, 'A' before 'a'.
 @table @code
 @item ?
 Not all shells correctly reset @samp{$?} after conditionals (@pxref{if,
@@ -17632,7 +17632,7 @@ often possible to avoid this problem using @samp{echo 
"x$word"}, taking
 the @samp{x} into account later in the pipe.  Many of these limitations
 can be worked around using M4sh (@pxref{Programming in M4sh}).
 
-@c This table includes things like `@command{test} (files)', so we can't
+@c This table includes things like '@command{test} (files)', so we can't
 @c use @table @command.
 @table @asis
 @item @command{.}
@@ -17656,7 +17656,7 @@ $ @kbd{echo 'fi' > syntax}
 $ @kbd{bash -c '. ./syntax; echo $?'}
 ./syntax: line 1: syntax error near unexpected token `fi'
 ./syntax: line 1: `fi'
-1
+2
 $ @kbd{ash -c '. ./syntax; echo $?'}
 ./syntax: 1: Syntax error: "fi" unexpected
 $ @kbd{zsh -c '. ./syntax; echo $?'}
@@ -18846,7 +18846,7 @@ files).
 @item @command{true}
 @c -----------------
 @prindex @command{true}
-@c Info cannot handle `:' in index entries.
+@c Info cannot handle ':' in index entries.
 @c @prindex @command{:}
 Don't worry: as far as we know @command{true} is portable.
 Nevertheless, it's not always a builtin (e.g., Bash 1.x), and the
@@ -18921,7 +18921,7 @@ include some limitations you should be aware of.
 @comment mention all the tools in GNU Coding Standards ``Utilities in
 @comment Makefiles''.
 
-@c This table includes things like `@command{expr} (|)', so we can't
+@c This table includes things like '@command{expr} (|)', so we can't
 @c use @table @command.
 @table @asis
 @anchor{awk}
@@ -21432,7 +21432,7 @@ $ @kbd{touch ../newer.x}
 $ @kbd{make}        # GNU make
 Building bar.x
 cp bar.x bar.y
-cp: cannot stat `bar.x': No such file or directory
+cp: cannot stat 'bar.x': No such file or directory
 make: *** [bar.y] Error 1
 $ @kbd{pmake}       # NetBSD make
 Building ../bar.x
@@ -21441,7 +21441,7 @@ $ @kbd{rm bar.y}
 $ @kbd{fmake}       # FreeBSD make, OpenBSD make
 echo Building bar.x
 cp bar.x bar.y
-cp: cannot stat `bar.x': No such file or directory
+cp: cannot stat 'bar.x': No such file or directory
 *** Error code 1
 $ @kbd{tmake}       # Tru64 make
 Building bar.x
@@ -21474,7 +21474,7 @@ cp ../bar.x bar.y
 $ @kbd{rm bar.y}
 $ @kbd{fmake}       # FreeBSD make, OpenBSD make
 cp bar.x bar.y
-cp: cannot stat `bar.x': No such file or directory
+cp: cannot stat 'bar.x': No such file or directory
 *** Error code 1
 $ @kbd{tmake}       # Tru64 make
 cp ../bar.x bar.y
@@ -22647,7 +22647,7 @@ specified neither @option{--with-readline} nor 
@option{--without-readline},
 you want to enable support for readline only if the library is available
 on the system.
 
-@c FIXME: Remove AS_IF when the problem of AC_REQUIRE within `if' is solved.
+@c FIXME: Remove AS_IF when the problem of AC_REQUIRE within 'if' is solved.
 @example
 AC_ARG_WITH([readline],
   [AS_HELP_STRING([--with-readline],
@@ -22673,7 +22673,7 @@ The next example shows how to use @code{AC_ARG_WITH} to 
give the user the
 possibility to enable support for the readline library, in case it is still
 experimental and not well tested, and is therefore disabled by default.
 
-@c FIXME: Remove AS_IF when the problem of AC_REQUIRE within `if' is solved.
+@c FIXME: Remove AS_IF when the problem of AC_REQUIRE within 'if' is solved.
 @example
 AC_ARG_WITH([readline],
   [AS_HELP_STRING([--with-readline],
@@ -22697,7 +22697,7 @@ The last example shows how to use @code{AC_ARG_WITH} to 
give the user the
 possibility to disable support for the readline library, given that it is
 an important feature and that it should be enabled by default.
 
-@c FIXME: Remove AS_IF when the problem of AC_REQUIRE within `if' is solved.
+@c FIXME: Remove AS_IF when the problem of AC_REQUIRE within 'if' is solved.
 @example
 AC_ARG_WITH([readline],
   [AS_HELP_STRING([--without-readline],
@@ -23643,7 +23643,7 @@ This macro is equivalent to:
 @example
 AC_CHECK_TYPE([@var{type}], [],
   [AC_DEFINE_UNQUOTED([@var{type}], [@var{default}],
-     [Define to `@var{default}'
+     [Define to '@var{default}'
       if <sys/types.h> does not define.])])
 @end example
 
@@ -25041,7 +25041,7 @@ AC_INIT([Example], [1.0], [bug-example@@example.org])
 AM_TYPE_PTRDIFF_T
 $ @kbd{rm aclocal.m4}
 $ @kbd{autoupdate}
-autoupdate: `configure.ac' is updated
+autoupdate: 'configure.ac' is updated
 $ @kbd{cat configure.ac}
 AC_INIT([Example], [1.0], [bug-example@@example.org])
 AC_CHECK_TYPES([ptrdiff_t])
@@ -25490,8 +25490,8 @@ the point of view of the test suite, there remains a 
single environment,
 @var{host} = @var{build}.  The log contains relevant information on the
 state of the @var{build} machine, including some important environment
 variables.
-@c FIXME: How about having an M4sh macro to say `hey, log the value
-@c of `@dots{}'?  This would help both Autoconf and Autotest.
+@c FIXME: How about having an M4sh macro to say "hey, log the value
+@c of '@dots{}'"?  This would help both Autoconf and Autotest.
 
 @item tested programs
 The absolute file name and answers to @option{--version} of the tested
@@ -26700,7 +26700,7 @@ $ @kbd{cat configure.ac}
 @result{}AC_OUTPUT
 $ @kbd{autoconf}
 @result{}configure.ac:11: warning: AC_REQUIRE:
-@result{} `TESTA' was expanded before it was required
+@result{} 'TESTA' was expanded before it was required
 @result{}configure.ac:4: TESTB is expanded from...
 @result{}configure.ac:6: TESTC is expanded from...
 @result{}configure.ac:7: OUTER is expanded from...
diff --git a/lib/Autom4te/C4che.pm b/lib/Autom4te/C4che.pm
index f5164811..5fe391ed 100644
--- a/lib/Autom4te/C4che.pm
+++ b/lib/Autom4te/C4che.pm
@@ -1,4 +1,4 @@
-# autoconf -- create `configure' using m4 macros
+# autoconf -- create 'configure' using m4 macros
 # Copyright (C) 2003, 2006, 2009-2017, 2020-2021 Free Software
 # Foundation, Inc.
 
diff --git a/lib/Autom4te/General.pm b/lib/Autom4te/General.pm
index fac67ab1..e2f3d6d3 100644
--- a/lib/Autom4te/General.pm
+++ b/lib/Autom4te/General.pm
@@ -1,4 +1,4 @@
-# autoconf -- create `configure' using m4 macros
+# autoconf -- create 'configure' using m4 macros
 # Copyright (C) 2001-2004, 2006-2007, 2009-2017, 2020-2021 Free Software
 # Foundation, Inc.
 
@@ -68,7 +68,7 @@ our @EXPORT = (@export_vars, @export_subs, 
@export_forward_subs);
 
 
 # Variable we share with the main package.  Be sure to have a single
-# copy of them: using `my' together with multiple inclusion of this
+# copy of them: using 'my' together with multiple inclusion of this
 # package would introduce several copies.
 
 =head2 Global Variables
@@ -166,7 +166,7 @@ sub END
   #
   #  1) normal termination
   #     this sets $? = 0
-  #  2) calling `exit (n)'
+  #  2) calling 'exit (n)'
   #     this sets $? = n
   #  3) calling die or friends (croak, confess...):
   #     a) when $! is non-0
@@ -180,9 +180,9 @@ sub END
   # Cases 1), 2), and 3b) are fine, but we prefer $? = 1 for 3a) and 3c).
   my $status = $?;
   $status = 1 if ($! && $! == $?) || $? == 255;
-  # (Note that we cannot safely distinguish calls to `exit (n)'
-  # from calls to die when `$! = n'.  It's not big deal because
-  # we only call `exit (0)' or `exit (1)'.)
+  # (Note that we cannot safely distinguish calls to 'exit (n)'
+  # from calls to die when '$! = n'.  It's not big deal because
+  # we only call 'exit (0)' or 'exit (1)'.)
 
   # This is required if the code might send any output to stdout
   # E.g., even --version or --help.  So it's best to do it unconditionally.
diff --git a/lib/Autom4te/Request.pm b/lib/Autom4te/Request.pm
index 67a60074..308a8922 100644
--- a/lib/Autom4te/Request.pm
+++ b/lib/Autom4te/Request.pm
@@ -1,4 +1,4 @@
-# autoconf -- create `configure' using m4 macros
+# autoconf -- create 'configure' using m4 macros
 # Copyright (C) 2001-2003, 2009-2017, 2020-2021 Free Software
 # Foundation, Inc.
 
diff --git a/lib/autoconf/autoconf.m4 b/lib/autoconf/autoconf.m4
index c1c2c789..fa909562 100644
--- a/lib/autoconf/autoconf.m4
+++ b/lib/autoconf/autoconf.m4
@@ -51,7 +51,7 @@ m4_include([autoconf/specific.m4])
 m4_include([autoconf/oldnames.m4])
 
 # We discourage the use of the non prefixed macro names: M4sugar maps
-# all the builtins into `m4_'.  Autoconf has been converted to these
+# all the builtins into 'm4_'.  Autoconf has been converted to these
 # names too.  But users may still depend upon these, so reestablish
 # them.
 
diff --git a/lib/autoconf/autoheader.m4 b/lib/autoconf/autoheader.m4
index 0611e4bf..bbd691f5 100644
--- a/lib/autoconf/autoheader.m4
+++ b/lib/autoconf/autoheader.m4
@@ -32,7 +32,7 @@
 # AH_OUTPUT(KEY, TEXT)
 # --------------------
 # Pass TEXT to autoheader.
-# This macro is `read' only via `autoconf --trace', it outputs nothing.
+# This macro is 'read' only via 'autoconf --trace', it outputs nothing.
 m4_define([AH_OUTPUT], [])
 
 
@@ -61,7 +61,7 @@ m4_define([AH_TEMPLATE],
 
 # AH_TOP(TEXT)
 # ------------
-# Output TEXT at the top of `config.h.in'.
+# Output TEXT at the top of 'config.h.in'.
 m4_define([AH_TOP],
 [m4_define([_AH_COUNTER], m4_incr(_AH_COUNTER))dnl
 AH_VERBATIM([0000]_AH_COUNTER, [$1])])
@@ -69,7 +69,7 @@ AH_VERBATIM([0000]_AH_COUNTER, [$1])])
 
 # AH_BOTTOM(TEXT)
 # ---------------
-# Output TEXT at the bottom of `config.h.in'.
+# Output TEXT at the bottom of 'config.h.in'.
 m4_define([AH_BOTTOM],
 [m4_define([_AH_COUNTER], m4_incr(_AH_COUNTER))dnl
 AH_VERBATIM([zzzz]_AH_COUNTER, [$1])])
diff --git a/lib/autoconf/autoscan.m4 b/lib/autoconf/autoscan.m4
index 450a6d58..be194f66 100644
--- a/lib/autoconf/autoscan.m4
+++ b/lib/autoconf/autoscan.m4
@@ -26,7 +26,7 @@
 
 # Written by Akim Demaille.
 
-# The prefix `AN' is chosen after `AutoscaN'.
+# The prefix 'AN' is chosen after 'AutoscaN'.
 
 # AN_OUTPUT(KIND, WORD, MACROS)
 # -----------------------------
diff --git a/lib/autoconf/autoupdate.m4 b/lib/autoconf/autoupdate.m4
index 2b495d30..4c05786f 100644
--- a/lib/autoconf/autoupdate.m4
+++ b/lib/autoconf/autoupdate.m4
@@ -60,7 +60,7 @@ m4_define([AU_DEFINE], [])
 #
 # This allows sharing the same code for both supporting obsoleted macros,
 # and to update a configure.ac.
-# See the end of `autoupdate.in' for a longer description.
+# See the end of 'autoupdate.in' for a longer description.
 m4_define([AU_DEFUN],
 [# This is what autoupdate's m4 run will expand.  It fires the warning
 # (with _au_warn_XXX), outputs it into the updated configure.ac (with
@@ -91,10 +91,10 @@ m4_define([_au_warn_$1], [])])
 m4_case([$4],
   [silent], [AC_DEFUN([$1], [$2])],
   [],       [AC_DEFUN([$1],
-        [m4_warn([obsolete], [The macro `$1' is obsolete.
+        [m4_warn([obsolete], [The macro '$1' is obsolete.
 You should run autoupdate.])dnl
 $2])],
-  [m4_fatal([SILENT argument to `$0' must be either empty or `silent'])]dnl
+  [m4_fatal([SILENT argument to '$0' must be either empty or 'silent'])]dnl
 )])
 
 
@@ -106,7 +106,7 @@ $2])],
 # This macro makes it possible to distinguish such cases.
 # The SILENT argument works the same as for AU_DEFUN.
 #
-# Do not use `defn' since then autoupdate would replace an old macro
+# Do not use 'defn' since then autoupdate would replace an old macro
 # call with the new macro body instead of the new macro call.
 #
 # Moreover, we have to take care that calls without parameters are
diff --git a/lib/autoconf/c.m4 b/lib/autoconf/c.m4
index 768c59aa..44443a39 100644
--- a/lib/autoconf/c.m4
+++ b/lib/autoconf/c.m4
@@ -100,7 +100,7 @@ int
 main (void)
 {
 dnl Do *not* indent the following line: there may be CPP directives.
-dnl Don't move the `;' right after for the same reason.
+dnl Don't move the ';' right after for the same reason.
 $2
   ;
   return 0;
@@ -176,8 +176,8 @@ choke me
 # -------------------------------------------------
 # Return a program that is valid if EXPRESSION is nonzero.
 # EXPRESSION must be an integer constant expression.
-# Be sure to use this array to avoid `unused' warnings, which are even
-# errors with `-W error'.
+# Be sure to use this array to avoid 'unused' warnings, which are even
+# errors with '-W error'.
 m4_define([AC_LANG_BOOL_COMPILE_TRY(C)],
 [AC_LANG_PROGRAM([$1], [static int test_array @<:@1 - 2 * !($2)@:>@;
 test_array @<:@0@:>@ = 0;
@@ -187,7 +187,7 @@ return test_array @<:@0@:>@;
 
 # AC_LANG_INT_SAVE(C)(PROLOGUE, EXPRESSION)
 # -----------------------------------------
-# We need `stdio.h' to open a `FILE' and `stdlib.h' for `exit'.
+# We need 'stdio.h' to open a 'FILE' and 'stdlib.h' for 'exit'.
 # But we include them only after the EXPRESSION has been evaluated.
 m4_define([AC_LANG_INT_SAVE(C)],
 [AC_LANG_PROGRAM([$1
@@ -376,7 +376,7 @@ ac_preproc_ok=:
 break])
 
 done
-# Because of `break', _AC_PREPROC_IFELSE's cleaning code was skipped.
+# Because of 'break', _AC_PREPROC_IFELSE's cleaning code was skipped.
 rm -f conftest.i conftest.err conftest.$ac_ext
 AS_IF([$ac_preproc_ok], [$1], [$2])
 ])# _AC_PROG_PREPROC_WORKS_IFELSE
@@ -688,7 +688,7 @@ AU_DEFUN([ac_cv_prog_gxx],
 # for (if not specified, a default list is used).  This just gives the
 # user an opportunity to specify an alternative search list for the C++
 # compiler.
-# aCC  HP-UX C++ compiler much better than `CC', so test before.
+# aCC  HP-UX C++ compiler much better than 'CC', so test before.
 # FCC   Fujitsu C++ compiler
 # KCC  KAI C++ compiler
 # RCC  Rational C++
@@ -782,8 +782,8 @@ fi[]dnl
 
 # AC_PROG_CXX_C_O
 # ---------------
-# Test if the C++ compiler accepts the options `-c' and `-o'
-# simultaneously, and define `CXX_NO_MINUS_C_MINUS_O' if it does not.
+# Test if the C++ compiler accepts the options '-c' and '-o'
+# simultaneously, and define 'CXX_NO_MINUS_C_MINUS_O' if it does not.
 AC_DEFUN([AC_PROG_CXX_C_O],
 [AC_REQUIRE([AC_PROG_CXX])dnl
 AC_LANG_PUSH([C++])dnl
@@ -791,7 +791,7 @@ AC_CACHE_CHECK([whether $CXX understands -c and -o 
together],
               [ac_cv_prog_cxx_c_o],
 [AC_LANG_CONFTEST([AC_LANG_PROGRAM([])])
 # We test twice because some compilers refuse to overwrite an existing
-# `.o' file with `-o', although they will create one.
+# '.o' file with '-o', although they will create one.
 ac_try='$CXX $CXXFLAGS -c conftest.$ac_ext -o conftest2.$ac_objext 
>&AS_MESSAGE_LOG_FD'
 rm -f conftest2.*
 if _AC_DO_VAR(ac_try) &&
@@ -1112,7 +1112,7 @@ fi[]dnl
 # main with its usual two arguments, to give the test fragments some
 # convenient non-compile-time-constant values to pass around.  In main,
 # there is an int variable 'ok' which will eventually become the return
-# value; use `ok |= ...' to consume the results of operations.
+# value; use 'ok |= ...' to consume the results of operations.
 #
 # Warning: each test program may only use the headers required to
 # exist in the relevant standard's *freestanding* environment, in case
@@ -1576,14 +1576,14 @@ m4_define([_AC_C_C11_OPTIONS], [
 #
 # If we find a way to make the test program compile, set cache variable
 # ac_cv_prog_cc_cEDITION to the options required (if any), and add those
-# options to $CC.  Set shell variable ac_prog_cc_stdc to `cEDITION',
+# options to $CC.  Set shell variable ac_prog_cc_stdc to 'cEDITION',
 # and set shell variable ac_cv_prog_cc_stdc to the options required.
 # (Neither of these variables is AC_SUBSTed.  ac_cv_prog_cc_stdc used
 # to be a cache variable and is preserved with this name for backward
-# compatibility.)  Otherwise, ac_cv_prog_cc_cEDITION is set to `no'
+# compatibility.)  Otherwise, ac_cv_prog_cc_cEDITION is set to 'no'
 # and the other variables are not changed.
 #
-# If ac_prog_cc_stdc is already set to a value other than `no',
+# If ac_prog_cc_stdc is already set to a value other than 'no',
 # the shell code produced by this macro does nothing.  This is so
 # _AC_PROG_CC_STDC_EDITION can use m4_map to iterate through
 # all the editions.
@@ -1702,7 +1702,7 @@ AU_DEFUN([AC_C_CROSS], [])
 # ------------------
 AC_DEFUN([AC_C_CHAR_UNSIGNED],
 [AH_VERBATIM([__CHAR_UNSIGNED__],
-[/* Define to 1 if type `char' is unsigned and your compiler does not
+[/* Define to 1 if type 'char' is unsigned and your compiler does not
    predefine this macro.  */
 #ifndef __CHAR_UNSIGNED__
 # undef __CHAR_UNSIGNED__
@@ -1940,7 +1940,7 @@ $ac_kw foo_t foo (void) {return 0; }
 done
 ])
 AH_VERBATIM([inline],
-[/* Define to `__inline__' or `__inline' if that's what the C compiler
+[/* Define to '__inline__' or '__inline' if that's what the C compiler
    calls it, or to nothing if 'inline' is not supported under any name.  */
 #ifndef __cplusplus
 #undef inline
@@ -2022,7 +2022,7 @@ AC_DEFUN([AC_C_CONST],
                   [ac_cv_c_const=no])])
 if test $ac_cv_c_const = no; then
   AC_DEFINE(const,,
-           [Define to empty if `const' does not conform to ANSI C.])
+           [Define to empty if 'const' does not conform to ANSI C.])
 fi
 ])# AC_C_CONST
 
@@ -2105,8 +2105,8 @@ return !x && !y;])],
                   [ac_cv_c_volatile=no])])
 if test $ac_cv_c_volatile = no; then
   AC_DEFINE(volatile,,
-           [Define to empty if the keyword `volatile' does not work.
-            Warning: valid code using `volatile' can become incorrect
+           [Define to empty if the keyword 'volatile' does not work.
+            Warning: valid code using 'volatile' can become incorrect
             without.  Disable with care.])
 fi
 ])# AC_C_VOLATILE
@@ -2114,7 +2114,7 @@ fi
 
 # AC_C_STRINGIZE
 # --------------
-# Checks if `#' can be used to glue strings together at the CPP level.
+# Checks if '#' can be used to glue strings together at the CPP level.
 # Defines HAVE_STRINGIZE if positive.
 AC_DEFUN([AC_C_STRINGIZE],
 [AC_CACHE_CHECK([for preprocessor stringizing operator],
@@ -2170,7 +2170,7 @@ AC_DEFUN([AC_C_FLEXIBLE_ARRAY_MEMBER],
   if test $ac_cv_c_flexmember = yes; then
     AC_DEFINE([FLEXIBLE_ARRAY_MEMBER], [],
       [Define to nothing if C supports flexible array members, and to
-       1 if it does not.  That way, with a declaration like `struct s
+       1 if it does not.  That way, with a declaration like 'struct s
        { int n; double d@<:@FLEXIBLE_ARRAY_MEMBER@:>@; };', the struct hack
        can be used with pre-C99 compilers.
        When computing the size of such an object, don't use 'sizeof (struct s)'
@@ -2733,14 +2733,14 @@ m4_define([_AC_CXX_CXX11_OPTIONS], [
 #
 # If we find a way to make the test program compile, set cache variable
 # ac_cv_prog_cxx_cxxEDITION to the options required (if any), and add those
-# options to $CXX.  Set shell variable ac_prog_cxx_stdcxx to `cxxEDITION',
+# options to $CXX.  Set shell variable ac_prog_cxx_stdcxx to 'cxxEDITION',
 # and set shell variable ac_cv_prog_cxx_stdcxx to the options required.
 # (Neither of these variables is AC_SUBSTed.  ac_cv_prog_cxx_stdcxx used
 # to be a cache variable and is preserved with this name for backward
-# compatibility.)  Otherwise, ac_cv_prog_cxx_cxxEDITION is set to `no'
+# compatibility.)  Otherwise, ac_cv_prog_cxx_cxxEDITION is set to 'no'
 # and the other variables are not changed.
 #
-# If ac_prog_cxx_stdcxx is already set to a value other than `no',
+# If ac_prog_cxx_stdcxx is already set to a value other than 'no',
 # the shell code produced by this macro does nothing.  This is so
 # _AC_PROG_CXX_STDCXX_EDITION can use m4_map to iterate through
 # all the editions.
diff --git a/lib/autoconf/fortran.m4 b/lib/autoconf/fortran.m4
index 641c5fb6..dd9d4bd4 100644
--- a/lib/autoconf/fortran.m4
+++ b/lib/autoconf/fortran.m4
@@ -309,7 +309,7 @@ AC_DEFUN([_AC_FC_DIALECT_YEAR],
 #  pgf77/pgf90/pghpf/pgf95/pgfortran: Portland Group F77/F90/F95 compilers
 #  xlf/xlf90/xlf95: IBM (AIX) F77/F90/F95 compilers
 #    Prefer xlf9x to the generic names because they do not reject files
-#    with extension `.f'.
+#    with extension '.f'.
 #  lf95: Lahey-Fujitsu F95 compiler
 #  fl32: Microsoft Fortran 77 "PowerStation" compiler
 #  af77: Apogee F77 compiler for Intergraph hardware running CLIX
@@ -342,7 +342,7 @@ rm -f a.out
 
 m4_expand_once([_AC_COMPILER_EXEEXT])[]dnl
 m4_expand_once([_AC_COMPILER_OBJEXT])[]dnl
-# If we don't use `.F' as extension, the preprocessor is not run on the
+# If we don't use '.F' as extension, the preprocessor is not run on the
 # input file.  (Note that this only needs to work for GNU compilers.)
 ac_save_ext=$ac_ext
 ac_ext=F
@@ -428,8 +428,8 @@ fi[]dnl
 
 # _AC_PROG_FC_C_O
 # ---------------
-# Test if the Fortran compiler accepts the options `-c' and `-o'
-# simultaneously, and define `[F77/FC]_NO_MINUS_C_MINUS_O' if it does not.
+# Test if the Fortran compiler accepts the options '-c' and '-o'
+# simultaneously, and define '[F77/FC]_NO_MINUS_C_MINUS_O' if it does not.
 #
 # The usefulness of this macro is questionable, as I can't really see
 # why anyone would use it.  The only reason I include it is for
@@ -442,7 +442,7 @@ AC_CACHE_CHECK([whether $[]_AC_FC[] understands -c and -o 
together],
               [ac_cv_prog_[]_AC_LANG_ABBREV[]_c_o],
 [AC_LANG_CONFTEST([AC_LANG_PROGRAM([])])
 # We test twice because some compilers refuse to overwrite an existing
-# `.o' file with `-o', although they will create one.
+# '.o' file with '-o', although they will create one.
 ac_try='$[]_AC_FC[] $[]_AC_LANG_PREFIX[]FLAGS -c conftest.$ac_ext -o 
conftest2.$ac_objext >&AS_MESSAGE_LOG_FD'
 rm -f conftest2.*
 if _AC_DO_VAR(ac_try) &&
@@ -821,11 +821,11 @@ AS_IF([test "$[]_AC_FC[]_DUMMY_MAIN" != unknown],
       [m4_default([$1],
 [if test $[]_AC_FC[]_DUMMY_MAIN != none; then
   AC_DEFINE_UNQUOTED([]_AC_FC[]_DUMMY_MAIN, $[]_AC_FC[]_DUMMY_MAIN,
-                    [Define to dummy `main' function (if any) required to
+                    [Define to dummy 'main' function (if any) required to
                      link to the Fortran libraries.])
   if test "x$ac_cv_fc_dummy_main" = "x$ac_cv_f77_dummy_main"; then
        AC_DEFINE([FC_DUMMY_MAIN_EQ_F77], 1,
-                 [Define if F77 and FC dummy `main' functions are identical.])
+                 [Define if F77 and FC dummy 'main' functions are identical.])
   fi
 fi])],
       [m4_default([$2],
@@ -886,8 +886,8 @@ AC_CACHE_CHECK([for alternate main to link with _AC_LANG 
libraries],
  LIBS=$ac_[]_AC_LANG_ABBREV[]_m_save_LIBS
 ])
 AC_DEFINE_UNQUOTED([]_AC_FC[]_MAIN, $ac_cv_[]_AC_LANG_ABBREV[]_main,
-                  [Define to alternate name for `main' routine that is
-                   called from a `main' in the Fortran libraries.])
+                  [Define to alternate name for 'main' routine that is
+                   called from a 'main' in the Fortran libraries.])
 ])# _AC_FC_MAIN
 
 
@@ -1205,7 +1205,7 @@ AC_LANG_POP(Fortran)dnl
 #
 # Some compilers allow preprocessing with either a Fortran preprocessor or
 # with the C preprocessor (cpp).  Prefer the Fortran preprocessor, to deal
-# correctly with continuation lines, `//' (not a comment), and preserve white
+# correctly with continuation lines, '//' (not a comment), and preserve white
 # space (for fixed form).
 #
 # (The flags for the current source-code extension, if any, are stored in
@@ -1459,7 +1459,7 @@ AC_LANG_POP([Fortran])dnl
 # ------------------------------------------------
 # Look for a compiler flag to make the Fortran (FC) compiler accept long lines
 # in the current (free- or fixed-format) source code, and adds it to FCFLAGS.
-# The optional LENGTH may be 80, 132 (default), or `unlimited' for longer
+# The optional LENGTH may be 80, 132 (default), or 'unlimited' for longer
 # lines.  Note that line lengths above 250 columns are not portable, and some
 # compilers (hello ifort) do not accept more than 132 columns at least for
 # fixed format.  Call ACTION-IF-SUCCESS (defaults to nothing) if successful
@@ -1503,7 +1503,7 @@ m4_case(m4_default([$1], [132]),
   [80],             [ac_fc_line_len=80
                       ac_fc_line_length_test='
       subroutine 
longer_than_72(arg1,arg2,arg3,arg4,arg5,arg6,arg7,arg8,arg9)'],
-  [m4_warning([Invalid length argument `$1'])])
+  [m4_warning([Invalid length argument '$1'])])
 : ${ac_fc_line_len_string=$ac_fc_line_len}
 AC_CACHE_CHECK(
 [for Fortran flag needed to accept $ac_fc_line_len_string column source lines],
diff --git a/lib/autoconf/functions.m4 b/lib/autoconf/functions.m4
index c5add9f8..30273b1f 100644
--- a/lib/autoconf/functions.m4
+++ b/lib/autoconf/functions.m4
@@ -76,7 +76,7 @@ AS_VAR_POPDEF([ac_var])])# AC_CHECK_FUNC
 # Prepare the autoheader snippet for FUNCTION.
 m4_define([_AH_CHECK_FUNC],
 [AH_TEMPLATE(AS_TR_CPP([HAVE_$1]),
-  [Define to 1 if you have the `$1' function.])])
+  [Define to 1 if you have the '$1' function.])])
 
 # _AC_CHECK_FUNCS_ONE_U(FUNCTION)
 # -------------------------------
@@ -113,7 +113,7 @@ m4_define([_AC_CHECK_FUNCS_ONE_C],
 # ACTION-IF-FOUND or ACTION-IF-NOT-FOUND for each function.
 # Additionally, make the preprocessor definition HAVE_FUNCTION
 # available for each found function.  Either ACTION may include
-# `break' to stop the search.
+# 'break' to stop the search.
 AC_DEFUN([AC_CHECK_FUNCS],
 [_$0(m4_validate_w([$1]), [$2], [$3])])
 
@@ -501,7 +501,7 @@ rm -f conftest.chown
 ])
 if test $ac_cv_func_chown_works = yes; then
   AC_DEFINE(HAVE_CHOWN, 1,
-           [Define to 1 if your system has a working `chown' function.])
+           [Define to 1 if your system has a working 'chown' function.])
 fi
 ])# AC_FUNC_CHOWN
 
@@ -524,7 +524,7 @@ AC_CACHE_CHECK([whether closedir returns void],
               [ac_cv_func_closedir_void=yes])])
 if test $ac_cv_func_closedir_void = yes; then
   AC_DEFINE(CLOSEDIR_VOID, 1,
-           [Define to 1 if the `closedir' function returns void instead
+           [Define to 1 if the 'closedir' function returns void instead
             of int.])
 fi
 ])
@@ -597,7 +597,7 @@ AS_IF([test $$2 = yes], [$3], [$4])
 AC_DEFUN([AC_FUNC_FNMATCH],
 [_AC_FUNC_FNMATCH_IF([POSIX], [ac_cv_func_fnmatch_works],
                     [AC_DEFINE([HAVE_FNMATCH], 1,
-                    [Define to 1 if your system has a working POSIX `fnmatch'
+                    [Define to 1 if your system has a working POSIX 'fnmatch'
                      function.])])
 ])# AC_FUNC_FNMATCH
 
@@ -669,7 +669,7 @@ fi
 
 # AC_FUNC_GETGROUPS
 # -----------------
-# Try to find `getgroups', and check that it works.
+# Try to find 'getgroups', and check that it works.
 # When cross-compiling, assume getgroups is broken.
 AN_FUNCTION([getgroups], [AC_FUNC_GETGROUPS])
 AC_DEFUN([AC_FUNC_GETGROUPS],
@@ -707,7 +707,7 @@ fi
 case "$ac_cv_func_getgroups_works" in
   *yes)
     AC_DEFINE(HAVE_GETGROUPS, 1,
-             [Define to 1 if your system has a working `getgroups' function.])
+             [Define to 1 if your system has a working 'getgroups' function.])
     ;;
 esac
 LIBS=$ac_save_LIBS
@@ -716,10 +716,10 @@ LIBS=$ac_save_LIBS
 
 # _AC_LIBOBJ_GETLOADAVG
 # ---------------------
-# Set up the AC_LIBOBJ replacement of `getloadavg'.
+# Set up the AC_LIBOBJ replacement of 'getloadavg'.
 m4_define([_AC_LIBOBJ_GETLOADAVG],
 [AC_LIBOBJ(getloadavg)
-AC_DEFINE(C_GETLOADAVG, 1, [Define to 1 if using `getloadavg.c'.])
+AC_DEFINE(C_GETLOADAVG, 1, [Define to 1 if using 'getloadavg.c'.])
 # Figure out what our getloadavg.c needs.
 AC_CHECK_FUNCS_ONCE([setlocale])
 ac_have_func=no
@@ -758,9 +758,9 @@ fi
 AC_CHECK_HEADERS(nlist.h,
 [AC_CHECK_MEMBERS([struct nlist.n_un.n_name],
                  [AC_DEFINE(NLIST_NAME_UNION, 1,
-                            [Define to 1 if your `struct nlist' has an
-                             `n_un' member.  Obsolete, depend on
-                             `HAVE_STRUCT_NLIST_N_UN_N_NAME])], [],
+                            [Define to 1 if your 'struct nlist' has an
+                             'n_un' member.  Obsolete, depend on
+                             'HAVE_STRUCT_NLIST_N_UN_N_NAME])], [],
                  [@%:@include <nlist.h>])
 ])dnl
 ])# _AC_LIBOBJ_GETLOADAVG
@@ -828,7 +828,7 @@ Yowza Am I SETGID yet
 if test $ac_cv_func_getloadavg_setgid = yes; then
   NEED_SETGID=true
   AC_DEFINE(GETLOADAVG_PRIVILEGED, 1,
-           [Define to 1 if the `getloadavg' function needs to be run setuid
+           [Define to 1 if the 'getloadavg' function needs to be run setuid
             or setgid.])
 else
   NEED_SETGID=false
@@ -873,7 +873,7 @@ AC_DEFUN([AC_FUNC_GETMNTENT],
 AC_SEARCH_LIBS(getmntent, [sun seq gen],
               [ac_cv_func_getmntent=yes
                AC_DEFINE([HAVE_GETMNTENT], 1,
-                         [Define to 1 if you have the `getmntent' function.])],
+                         [Define to 1 if you have the 'getmntent' function.])],
               [ac_cv_func_getmntent=no])
 ])
 
@@ -891,7 +891,7 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT], 
[getpgrp (0);])],
 ])
 if test $ac_cv_func_getpgrp_void = yes; then
   AC_DEFINE(GETPGRP_VOID, 1,
-           [Define to 1 if the `getpgrp' function requires zero arguments.])
+           [Define to 1 if the 'getpgrp' function requires zero arguments.])
 fi
 ])# AC_FUNC_GETPGRP
 
@@ -925,7 +925,7 @@ if test "$as_ln_s" = "ln -s" && ln -s conftest.file 
conftest.sym; then
                   *)      ac_cv_func_lstat_dereferences_slashed_symlink=no ;;
                 esac])
 else
-  # If the `ln -s' command failed, then we probably don't even
+  # If the 'ln -s' command failed, then we probably don't even
   # have an lstat function.
   ac_cv_func_lstat_dereferences_slashed_symlink=no
 fi
@@ -934,7 +934,7 @@ rm -f conftest.sym conftest.file
 
 test $ac_cv_func_lstat_dereferences_slashed_symlink = yes &&
   AC_DEFINE_UNQUOTED([LSTAT_FOLLOWS_SLASHED_SYMLINK], [1],
-                    [Define to 1 if `lstat' dereferences a symlink specified
+                    [Define to 1 if 'lstat' dereferences a symlink specified
                      with a trailing slash.])
 
 if test "x$ac_cv_func_lstat_dereferences_slashed_symlink" = xno; then
@@ -945,7 +945,7 @@ fi
 
 # _AC_FUNC_MALLOC_IF(IF-WORKS, IF-NOT)
 # ------------------------------------
-# If `malloc (0)' properly handled, run IF-WORKS, otherwise, IF-NOT.
+# If 'malloc (0)' properly handled, run IF-WORKS, otherwise, IF-NOT.
 AC_DEFUN([_AC_FUNC_MALLOC_IF],
 [AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
 AC_CACHE_CHECK([for GNU libc compatible malloc], ac_cv_func_malloc_0_nonnull,
@@ -972,13 +972,13 @@ AS_IF([test $ac_cv_func_malloc_0_nonnull = yes], [$1], 
[$2])
 
 # AC_FUNC_MALLOC
 # --------------
-# Report whether `malloc (0)' properly handled, and replace malloc if
+# Report whether 'malloc (0)' properly handled, and replace malloc if
 # needed.
 AN_FUNCTION([malloc], [AC_FUNC_MALLOC])
 AC_DEFUN([AC_FUNC_MALLOC],
 [_AC_FUNC_MALLOC_IF(
   [AC_DEFINE([HAVE_MALLOC], 1,
-            [Define to 1 if your system has a GNU libc compatible `malloc'
+            [Define to 1 if your system has a GNU libc compatible 'malloc'
              function, and to 0 otherwise.])],
   [AC_DEFINE([HAVE_MALLOC], 0)
    AC_LIBOBJ(malloc)
@@ -1406,7 +1406,7 @@ main (void)
                esac])])
 if test $ac_cv_func_mmap_fixed_mapped = yes; then
   AC_DEFINE([HAVE_MMAP], [1],
-           [Define to 1 if you have a working `mmap' system call.])
+           [Define to 1 if you have a working 'mmap' system call.])
 fi
 rm -f conftest.mmap conftest.txt
 ])# AC_FUNC_MMAP
@@ -1419,7 +1419,7 @@ AU_ALIAS([AC_MMAP], [AC_FUNC_MMAP])
 
 # AC_FUNC_OBSTACK
 # ---------------
-# Ensure obstack support.  Yeah, this is not exactly a `FUNC' check.
+# Ensure obstack support.  Yeah, this is not exactly a 'FUNC' check.
 AN_FUNCTION([obstack_init], [AC_FUNC_OBSTACK])
 AN_IDENTIFIER([obstack],    [AC_FUNC_OBSTACK])
 AC_DEFUN([AC_FUNC_OBSTACK],
@@ -1451,7 +1451,7 @@ AU_ALIAS([AM_FUNC_OBSTACK], [AC_FUNC_OBSTACK])
 
 # _AC_FUNC_REALLOC_IF(IF-WORKS, IF-NOT)
 # -------------------------------------
-# If `realloc (0, 0)' is properly handled, run IF-WORKS, otherwise, IF-NOT.
+# If 'realloc (0, 0)' is properly handled, run IF-WORKS, otherwise, IF-NOT.
 AC_DEFUN([_AC_FUNC_REALLOC_IF],
 [AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
 AC_CACHE_CHECK([for GNU libc compatible realloc], ac_cv_func_realloc_0_nonnull,
@@ -1478,13 +1478,13 @@ AS_IF([test $ac_cv_func_realloc_0_nonnull = yes], [$1], 
[$2])
 
 # AC_FUNC_REALLOC
 # ---------------
-# Report whether `realloc (0, 0)' is properly handled, and replace realloc if
+# Report whether 'realloc (0, 0)' is properly handled, and replace realloc if
 # needed.
 AN_FUNCTION([realloc], [AC_FUNC_REALLOC])
 AC_DEFUN([AC_FUNC_REALLOC],
 [_AC_FUNC_REALLOC_IF(
   [AC_DEFINE([HAVE_REALLOC], 1,
-            [Define to 1 if your system has a GNU libc compatible `realloc'
+            [Define to 1 if your system has a GNU libc compatible 'realloc'
              function, and to 0 otherwise.])],
   [AC_DEFINE([HAVE_REALLOC], 0)
    AC_LIBOBJ([realloc])
@@ -1495,9 +1495,9 @@ AC_DEFUN([AC_FUNC_REALLOC],
 
 # AC_FUNC_SELECT_ARGTYPES
 # -----------------------
-# Determine the correct type to be passed to each of the `select'
-# function's arguments, and define those types in `SELECT_TYPE_ARG1',
-# `SELECT_TYPE_ARG234', and `SELECT_TYPE_ARG5'.
+# Determine the correct type to be passed to each of the 'select'
+# function's arguments, and define those types in 'SELECT_TYPE_ARG1',
+# 'SELECT_TYPE_ARG234', and 'SELECT_TYPE_ARG5'.
 AC_DEFUN([AC_FUNC_SELECT_ARGTYPES],
 [AC_CHECK_HEADERS_ONCE([sys/select.h sys/socket.h])
 AC_CACHE_CHECK([types of arguments for select],
@@ -1529,11 +1529,11 @@ set dummy `echo "$ac_cv_func_select_args" | sed 
's/\*/\*/g'`
 IFS=$ac_save_IFS
 shift
 AC_DEFINE_UNQUOTED(SELECT_TYPE_ARG1, $[1],
-                  [Define to the type of arg 1 for `select'.])
+                  [Define to the type of arg 1 for 'select'.])
 AC_DEFINE_UNQUOTED(SELECT_TYPE_ARG234, ($[2]),
-                  [Define to the type of args 2, 3 and 4 for `select'.])
+                  [Define to the type of args 2, 3 and 4 for 'select'.])
 AC_DEFINE_UNQUOTED(SELECT_TYPE_ARG5, ($[3]),
-                  [Define to the type of arg 5 for `select'.])
+                  [Define to the type of arg 5 for 'select'.])
 rm -rf conftest*
 ])# AC_FUNC_SELECT_ARGTYPES
 
@@ -1550,7 +1550,7 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT], 
[setpgrp(0, 0);])],
 ])
 if test $ac_cv_func_setpgrp_void = yes; then
   AC_DEFINE(SETPGRP_VOID, 1,
-           [Define to 1 if the `setpgrp' function requires zero arguments.])
+           [Define to 1 if the 'setpgrp' function requires zero arguments.])
 fi
 ])# AC_FUNC_SETPGRP
 
@@ -1577,7 +1577,7 @@ AC_CACHE_CHECK([whether $1 accepts an empty string],
 if test $ac_cv_func_$1_empty_string_bug = yes; then
   AC_LIBOBJ([$1])
   AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_$1_EMPTY_STRING_BUG]), 1,
-                    [Define to 1 if `$1' has the bug that it succeeds when
+                    [Define to 1 if '$1' has the bug that it succeeds when
                      given the zero-length file name argument.])
 fi
 ])# _AC_FUNC_STAT
@@ -1691,7 +1691,7 @@ if test $ac_cv_have_decl_strerror_r = yes; then
   # For backward compatibility's sake, define HAVE_STRERROR_R.
   # (We used to run AC_CHECK_FUNCS_ONCE for strerror_r, as well
   # as AC_CHECK_DECLS_ONCE.)
-  AC_DEFINE([HAVE_STRERROR_R], [1], [Define if you have `strerror_r'.])
+  AC_DEFINE([HAVE_STRERROR_R], [1], [Define if you have 'strerror_r'.])
 fi
 
 AC_CACHE_CHECK([whether strerror_r returns char *],
@@ -1765,7 +1765,7 @@ test $ac_cv_func_strnlen_working = no && 
AC_LIBOBJ([strnlen])
 # ------------------------
 AC_DEFUN([AC_FUNC_SETVBUF_REVERSED],
 [m4_warn([obsolete],
-[The macro `$0' is obsolete.  Remove it and all references to 
SETVBUF_REVERSED.])dnl
+[The macro '$0' is obsolete.  Remove it and all references to 
SETVBUF_REVERSED.])dnl
 AC_CACHE_VAL([ac_cv_func_setvbuf_reversed], [ac_cv_func_setvbuf_reversed=no])
 ])# AC_FUNC_SETVBUF_REVERSED
 
@@ -1795,7 +1795,7 @@ AC_CACHE_CHECK(for working strcoll, 
ac_cv_func_strcoll_works,
                esac])])
 if test $ac_cv_func_strcoll_works = yes; then
   AC_DEFINE(HAVE_STRCOLL, 1,
-           [Define to 1 if you have the `strcoll' function and it is properly
+           [Define to 1 if you have the 'strcoll' function and it is properly
             defined.])
 fi
 ])# AC_FUNC_STRCOLL
@@ -1829,7 +1829,7 @@ AC_RUN_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT
 if test "x$ac_cv_func_utime_null" != xno; then
   ac_cv_func_utime_null=yes
   AC_DEFINE(HAVE_UTIME_NULL, 1,
-           [Define to 1 if `utime(file, NULL)' sets file's timestamp to the
+           [Define to 1 if 'utime(file, NULL)' sets file's timestamp to the
             present.])
 fi
 rm -f conftest.data
@@ -1876,12 +1876,12 @@ if test "x$ac_cv_func_fork_works" = xcross; then
 fi
 
 if test "x$ac_cv_func_vfork_works" = xyes; then
-  AC_DEFINE(HAVE_WORKING_VFORK, 1, [Define to 1 if `vfork' works.])
+  AC_DEFINE(HAVE_WORKING_VFORK, 1, [Define to 1 if 'vfork' works.])
 else
-  AC_DEFINE(vfork, fork, [Define as `fork' if `vfork' does not work.])
+  AC_DEFINE(vfork, fork, [Define as 'fork' if 'vfork' does not work.])
 fi
 if test "x$ac_cv_func_fork_works" = xyes; then
-  AC_DEFINE(HAVE_WORKING_FORK, 1, [Define to 1 if `fork' works.])
+  AC_DEFINE(HAVE_WORKING_FORK, 1, [Define to 1 if 'fork' works.])
 fi
 ])# AC_FUNC_FORK
 
@@ -2035,8 +2035,8 @@ AC_DEFUN([AC_FUNC_VPRINTF],
 AS_IF([test "x$ac_cv_func_vprintf" = xno],
 [AC_CHECK_FUNC([_doprnt],
               [AC_DEFINE([HAVE_DOPRNT], [1],
-                         [Define to 1 if you don't have `vprintf' but do have
-                         `_doprnt.'])])])])
+                         [Define to 1 if you don't have 'vprintf' but do have
+                         '_doprnt.'])])])])
 
 
 # AU::AC_VPRINTF
@@ -2052,8 +2052,8 @@ AU_ALIAS([AC_VPRINTF], [AC_FUNC_VPRINTF])
 AN_FUNCTION([wait3], [AC_FUNC_WAIT3])
 AC_DEFUN([AC_FUNC_WAIT3],
 [m4_warn([obsolete],
-[$0: `wait3' has been removed from POSIX.
-Remove this `AC_FUNC_WAIT3' and adjust your code to use `waitpid' instead.])dnl
+[$0: 'wait3' has been removed from POSIX.
+Remove this 'AC_FUNC_WAIT3' and adjust your code to use 'waitpid' instead.])dnl
 AC_CACHE_CHECK([for wait3 that fills in rusage],
               [ac_cv_func_wait3_rusage],
 [AC_RUN_IFELSE([AC_LANG_SOURCE(
@@ -2097,8 +2097,8 @@ main (void)
               [ac_cv_func_wait3_rusage=no])])
 if test $ac_cv_func_wait3_rusage = yes; then
   AC_DEFINE(HAVE_WAIT3, 1,
-           [Define to 1 if you have the `wait3' system call.
-            Deprecated, you should no longer depend upon `wait3'.])
+           [Define to 1 if you have the 'wait3' system call.
+            Deprecated, you should no longer depend upon 'wait3'.])
 fi
 ])# AC_FUNC_WAIT3
 
diff --git a/lib/autoconf/general.m4 b/lib/autoconf/general.m4
index 053130b3..ee38d8ff 100644
--- a/lib/autoconf/general.m4
+++ b/lib/autoconf/general.m4
@@ -37,12 +37,12 @@ Inc.
 
 # We heavily use m4's diversions both for the initializations and for
 # required macros (see AC_REQUIRE), because in both cases we have to
-# issue high in `configure' something which is discovered late.
+# issue high in 'configure' something which is discovered late.
 #
 # KILL is only used to suppress output.
 #
-# The layers of `configure'.  We let m4 undivert them by itself, when
-# it reaches the end of `configure.ac'.
+# The layers of 'configure'.  We let m4 undivert them by itself, when
+# it reaches the end of 'configure.ac'.
 #
 # - BINSH
 #   #! /bin/sh
@@ -61,7 +61,7 @@ Inc.
 #   initialization code, option handling loop.
 #
 # - HELP_BEGIN
-#   Handling `configure --help'.
+#   Handling 'configure --help'.
 # - HELP_CANON
 #   Help msg for AC_CANONICAL_*
 # - HELP_ENABLE
@@ -100,7 +100,7 @@ Inc.
 # Convert a diversion name into its number.  Otherwise, return
 # DIVERSION-NAME which is supposed to be an actual diversion number.
 # Of course it would be nicer to use m4_case here, instead of zillions
-# of little macros, but it then takes twice longer to run `autoconf'!
+# of little macros, but it then takes twice longer to run 'autoconf'!
 #
 # From M4sugar:
 #    -1. KILL
@@ -189,7 +189,7 @@ AC_DEFUN([AC_REQUIRE_SHELL_FN],
 # won't work in a normal autoconf run.
 AU_DEFUN([AC_FOREACH], [[m4_foreach_w($@)]])
 AC_DEFUN([AC_FOREACH], [m4_foreach_w($@)dnl
-m4_warn([obsolete], [The macro `AC_FOREACH' is obsolete.
+m4_warn([obsolete], [The macro 'AC_FOREACH' is obsolete.
 You should run autoupdate.])])
 
 
@@ -211,7 +211,7 @@ AU_ALIAS([AC_HELP_STRING], [AS_HELP_STRING])
 
 
 # It is suggested that the macros in this section appear before
-# AC_INIT in `configure.ac'.  Nevertheless, this is just stylistic,
+# AC_INIT in 'configure.ac'.  Nevertheless, this is just stylistic,
 # and from the implementation point of view, AC_INIT *must* be expanded
 # beforehand: it puts data in diversions which must appear before the
 # data provided by the macros of this section.
@@ -280,7 +280,7 @@ m4_define_default([AC_PACKAGE_URL],
 # AC_COPYRIGHT(TEXT, [VERSION-DIVERSION = VERSION_USER],
 #              [FILTER = m4_newline])
 # ------------------------------------------------------
-# Emit TEXT, a copyright notice, in the top of `configure' and in
+# Emit TEXT, a copyright notice, in the top of 'configure' and in
 # --version output.  Macros in TEXT are evaluated once.  Process
 # the --version output through FILTER (m4_newline, m4_do, and
 # m4_copyright_condense are common filters).
@@ -309,13 +309,13 @@ m4_define([AC_REVISION],
 
 # AU::AC_PREREQ(VERSION)
 # ----------------------
-# Update this `AC_PREREQ' statement to require the current version of
+# Update this 'AC_PREREQ' statement to require the current version of
 # Autoconf.  But fail if ever this autoupdate is too old.
 #
-# Note that `m4_defn([m4_PACKAGE_VERSION])' below are expanded before
-# calling `AU_DEFUN', i.e., it is hard coded.  Otherwise it would be
+# Note that 'm4_defn([m4_PACKAGE_VERSION])' below are expanded before
+# calling 'AU_DEFUN', i.e., it is hard coded.  Otherwise it would be
 # quite complex for autoupdate to import the value of
-# `m4_PACKAGE_VERSION'.  We could `AU_DEFUN' `m4_PACKAGE_VERSION', but
+# 'm4_PACKAGE_VERSION'.  We could 'AU_DEFUN' 'm4_PACKAGE_VERSION', but
 # this would replace all its occurrences with the current version of
 # Autoconf, which is certainly not what the user intended.
 AU_DEFUN([AC_PREREQ],
@@ -381,7 +381,7 @@ gives unlimited permission to copy, distribute and modify 
it.],
 
 # File Descriptors
 # ----------------
-# Set up the file descriptors used by `configure'.
+# Set up the file descriptors used by 'configure'.
 # File descriptor usage:
 # 0 standard input (/dev/null)
 # 1 file creation
@@ -402,8 +402,8 @@ AU_ALIAS([AC_FD_MSG], [AS_MESSAGE_FD])
 
 # _AC_INIT_DEFAULTS
 # -----------------
-# Values which defaults can be set from `configure.ac'.
-# `/bin/machine' is used in `glibcbug'.  The others are used in config.*
+# Values which defaults can be set from 'configure.ac'.
+# '/bin/machine' is used in 'glibcbug'.  The others are used in config.*
 m4_define([_AC_INIT_DEFAULTS],
 [m4_divert_push([DEFAULTS])dnl
 
@@ -469,10 +469,10 @@ AC_DEFUN([AC_PREFIX_DEFAULT],
 
 # AC_PREFIX_PROGRAM(PROGRAM)
 # --------------------------
-# Guess the value for the `prefix' variable by looking for
+# Guess the value for the 'prefix' variable by looking for
 # the argument program along PATH and taking its parent.
-# Example: if the argument is `gcc' and we find /usr/local/gnu/bin/gcc,
-# set `prefix' to /usr/local/gnu.
+# Example: if the argument is 'gcc' and we find /usr/local/gnu/bin/gcc,
+# set 'prefix' to /usr/local/gnu.
 # This comes too late to find a site file based on the prefix,
 # and it might use a cached value for the path.
 # No big loss, I think, since most configures don't use this macro anyway.
@@ -519,7 +519,7 @@ m4_divert_pop([PARSE_ARGS])dnl
 
 # _AC_INIT_SRCDIR
 # ---------------
-# Compute `srcdir' based on `$ac_unique_file'.
+# Compute 'srcdir' based on '$ac_unique_file'.
 #
 # (We have to AC_DEFUN it, since we use AC_REQUIRE.)
 #
@@ -543,7 +543,7 @@ if test ! -r "$srcdir/$ac_unique_file"; then
   test "$ac_srcdir_defaulted" = yes && srcdir="$ac_confdir or .."
   AC_MSG_ERROR([cannot find sources ($ac_unique_file) in $srcdir])
 fi
-ac_msg="sources are in $srcdir, but \`cd $srcdir' does not work"
+ac_msg="sources are in $srcdir, but 'cd $srcdir' does not work"
 ac_abs_confdir=`(
        cd "$srcdir" && test -r "./$ac_unique_file" || AC_MSG_ERROR([$ac_msg])
        pwd)`
@@ -903,8 +903,8 @@ do
   | --x-librar=* | --x-libra=* | --x-libr=* | --x-lib=* | --x-li=* | --x-l=*)
     x_libraries=$ac_optarg ;;
 
-  -*) AC_MSG_ERROR([unrecognized option: `$ac_option'
-Try `$[0] --help' for more information])
+  -*) AC_MSG_ERROR([unrecognized option: '$ac_option'
+Try '$[0] --help' for more information])
     ;;
 
   *=*)
@@ -912,7 +912,7 @@ Try `$[0] --help' for more information])
     # Reject names that are not valid shell variable names.
     case $ac_envvar in #(
       '' | [[0-9]]* | *[[!_$as_cr_alnum]]* )
-      AC_MSG_ERROR([invalid variable name: `$ac_envvar']) ;;
+      AC_MSG_ERROR([invalid variable name: '$ac_envvar']) ;;
     esac
     eval $ac_envvar=\$ac_optarg
     export $ac_envvar ;;
@@ -962,7 +962,7 @@ do
   AC_MSG_ERROR([expected an absolute directory name for --$ac_var: $ac_val])
 done
 
-# There might be people who depend on the old broken behavior: `$host'
+# There might be people who depend on the old broken behavior: '$host'
 # used to hold the argument of --host etc.
 # FIXME: To remove some day.
 build=$build_alias
@@ -999,10 +999,10 @@ m4_define([_AC_INIT_PARSE_ENABLE],
 
 # _AC_INIT_PARSE_ENABLE2(OPTION-NAME, POSITIVE-NAME)
 # --------------------------------------------------
-# Handle an `--enable' or a `--with' option.
+# Handle an '--enable' or a '--with' option.
 #
-# OPTION-NAME is `enable', `disable', `with', or `without'.
-# POSITIVE-NAME is the corresponding positive variant, i.e. `enable' or `with'.
+# OPTION-NAME is 'enable', 'disable', 'with', or 'without'.
+# POSITIVE-NAME is the corresponding positive variant, i.e. 'enable' or 'with'.
 #
 # Positive variant of the option is recognized by the condition
 #      OPTION-NAME == POSITIVE-NAME .
@@ -1013,7 +1013,7 @@ m4_define([_AC_INIT_PARSE_ENABLE2],
     # Reject names that are not valid shell variable names.
     expr "x$ac_useropt" : "[.*[^-+._$as_cr_alnum]]" >/dev/null &&
       AC_MSG_ERROR([invalid ]m4_if([$2], [with],
-        [package], [feature])[ name: `$ac_useropt'])
+        [package], [feature])[ name: '$ac_useropt'])
     ac_useropt_orig=$ac_useropt
     ac_useropt=`AS_ECHO(["$ac_useropt"]) | sed 's/[[-+.]]/_/g'`
     case $ac_user_opts in
@@ -1029,7 +1029,7 @@ m4_define([_AC_INIT_PARSE_ENABLE2],
 
 # _AC_INIT_HELP
 # -------------
-# Handle the `configure --help' message.
+# Handle the 'configure --help' message.
 m4_define([_AC_INIT_HELP],
 [m4_divert_push([HELP_BEGIN])dnl
 
@@ -1040,7 +1040,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures m4_ifset([AC_PACKAGE_STRING],
+'configure' configures m4_ifset([AC_PACKAGE_STRING],
                        [AC_PACKAGE_STRING],
                        [this package]) to adapt to many kinds of systems.
 
@@ -1056,11 +1056,11 @@ Configuration:
       --help=short        display options specific to this package
       --help=recursive    display the short help of all the included packages
   -V, --version           display version information and exit
-  -q, --quiet, --silent   do not print \`checking ...' messages
+  -q, --quiet, --silent   do not print 'checking ...' messages
       --cache-file=FILE   cache test results in FILE [disabled]
-  -C, --config-cache      alias for \`--cache-file=config.cache'
+  -C, --config-cache      alias for '--cache-file=config.cache'
   -n, --no-create         do not create output files
-      --srcdir=DIR        find the sources in DIR [configure dir or \`..']
+      --srcdir=DIR        find the sources in DIR [configure dir or '..']
 
 Installation directories:
 ]AS_HELP_STRING([--prefix=PREFIX],
@@ -1068,10 +1068,10 @@ Installation directories:
 AS_HELP_STRING([--exec-prefix=EPREFIX],
   [install architecture-dependent files in EPREFIX [PREFIX]])[
 
-By default, \`make install' will install all the files in
-\`$ac_default_prefix/bin', \`$ac_default_prefix/lib' etc.  You can specify
-an installation prefix other than \`$ac_default_prefix' using \`--prefix',
-for instance \`--prefix=\$HOME'.
+By default, 'make install' will install all the files in
+'$ac_default_prefix/bin', '$ac_default_prefix/lib' etc.  You can specify
+an installation prefix other than '$ac_default_prefix' using '--prefix',
+for instance '--prefix=\$HOME'.
 
 For better control, use the options below.
 
@@ -1177,7 +1177,7 @@ m4_divert_pop([HELP_END])dnl
 
 # _AC_INIT_VERSION
 # ----------------
-# Handle the `configure --version' message.
+# Handle the 'configure --version' message.
 m4_define([_AC_INIT_VERSION],
 [m4_divert_text([VERSION_BEGIN],
 [if $ac_init_version; then
@@ -1244,10 +1244,10 @@ _ACEOF
 
 # _AC_INIT_PREPARE
 # ----------------
-# Called by AC_INIT to build the preamble of the `configure' scripts.
+# Called by AC_INIT to build the preamble of the 'configure' scripts.
 # 1. Trap and clean up various tmp files.
 # 2. Set up the fd and output files
-# 3. Remember the options given to `configure' for `config.status --recheck'.
+# 3. Remember the options given to 'configure' for 'config.status --recheck'.
 # 4. Initiates confdefs.h
 # 5. Loads site and cache files
 m4_define([_AC_INIT_PREPARE],
@@ -1415,12 +1415,12 @@ AC_CONFIG_SRCDIR([$1])], [[AC_INIT]])])[]dnl
 # AC_INIT([PACKAGE, VERSION, [BUG-REPORT], [TARNAME], [URL])
 # ----------------------------------------------------------
 # Include the user macro files, prepare the diversions, and output the
-# preamble of the `configure' script.
+# preamble of the 'configure' script.
 #
 # If BUG-REPORT is omitted, do without (unless the user previously
 # defined the m4 macro AC_PACKAGE_BUGREPORT).  If TARNAME is omitted,
 # use PACKAGE to seed it.  If URL is omitted, use
-# `https://www.gnu.org/software/TARNAME/' if PACKAGE begins with `GNU',
+# 'https://www.gnu.org/software/TARNAME/' if PACKAGE begins with 'GNU',
 # otherwise, do without.
 #
 # Note that the order is important: first initialize, then set the
@@ -1430,7 +1430,7 @@ m4_define([AC_INIT],
 m4_pattern_forbid([^_?A[CHUM]_])
 m4_pattern_forbid([_AC_])
 m4_pattern_forbid([^LIBOBJS$],
-                 [do not use LIBOBJS directly, use AC_LIBOBJ (see section 
`AC_LIBOBJ vs LIBOBJS'])
+                 [do not use LIBOBJS directly, use AC_LIBOBJ (see section 
'AC_LIBOBJ vs LIBOBJS'])
 # Actually reserved by M4sh.
 m4_pattern_allow([^AS_FLAGS$])
 # So that the autoconf-generated scripts will always re-execute
@@ -1579,12 +1579,12 @@ AC_DEFUN([AC_DISABLE_OPTION_CHECKING],
 # AC_ARG_VAR(VARNAME, DOCUMENTATION)
 # ----------------------------------
 # Register VARNAME as a precious variable, and document it in
-# `configure --help' (but only once).
+# 'configure --help' (but only once).
 AC_DEFUN([AC_ARG_VAR],
 [m4_divert_once([HELP_VAR], [[
 Some influential environment variables:]])dnl
 m4_divert_once([HELP_VAR_END], [[
-Use these variables to override the choices made by `configure' or to help
+Use these variables to override the choices made by 'configure' or to help
 it to find libraries and programs with nonstandard names/locations.]])dnl
 m4_expand_once([m4_divert_text([HELP_VAR],
                               [AS_HELP_STRING([$1], [$2], [              ])])],
@@ -1611,7 +1611,7 @@ m4_define([_AC_ARG_VAR_PRECIOUS],
 # which represents the current run, and a second (ac_cv_env_) which,
 # at the first run, will be saved in the cache.  As an exception to
 # the cache mechanism, its loading will override these variables (non
-# `ac_cv_env_' cache value are only set when unset).
+# 'ac_cv_env_' cache value are only set when unset).
 #
 # In subsequent runs, after having loaded the cache, compare
 # ac_cv_env_foo against ac_env_foo.  See _AC_ARG_VAR_VALIDATE.
@@ -1629,15 +1629,15 @@ done])dnl
 # _AC_ARG_VAR_VALIDATE
 # --------------------
 # The precious variables are saved twice at the beginning of
-# configure.  E.g., PRECIOUS is saved as `ac_env_PRECIOUS_set' and
-# `ac_env_PRECIOUS_value' on the one hand and `ac_cv_env_PRECIOUS_set'
-# and `ac_cv_env_PRECIOUS_value' on the other hand.
+# configure.  E.g., PRECIOUS is saved as 'ac_env_PRECIOUS_set' and
+# 'ac_env_PRECIOUS_value' on the one hand and 'ac_cv_env_PRECIOUS_set'
+# and 'ac_cv_env_PRECIOUS_value' on the other hand.
 #
-# Now the cache has just been loaded, so `ac_cv_env_' represents the
-# content of the cached values, while `ac_env_' represents that of the
+# Now the cache has just been loaded, so 'ac_cv_env_' represents the
+# content of the cached values, while 'ac_env_' represents that of the
 # current values.
 #
-# So we check that `ac_env_' and `ac_cv_env_' are consistent.  If
+# So we check that 'ac_env_' and 'ac_cv_env_' are consistent.  If
 # they aren't, die.
 m4_define([_AC_ARG_VAR_VALIDATE],
 [m4_divert_text([INIT_PREPARE],
@@ -1651,10 +1651,10 @@ for ac_var in $ac_precious_vars; do
   eval ac_new_val=\$ac_env_${ac_var}_value
   case $ac_old_set,$ac_new_set in
     set,)
-      AS_MESSAGE([error: `$ac_var' was set to `$ac_old_val' in the previous 
run], 2)
+      AS_MESSAGE([error: '$ac_var' was set to '$ac_old_val' in the previous 
run], 2)
       ac_cache_corrupted=: ;;
     ,set)
-      AS_MESSAGE([error: `$ac_var' was not set in the previous run], 2)
+      AS_MESSAGE([error: '$ac_var' was not set in the previous run], 2)
       ac_cache_corrupted=: ;;
     ,);;
     *)
@@ -1663,14 +1663,14 @@ for ac_var in $ac_precious_vars; do
        ac_old_val_w=`echo x $ac_old_val`
        ac_new_val_w=`echo x $ac_new_val`
        if test "$ac_old_val_w" != "$ac_new_val_w"; then
-         AS_MESSAGE([error: `$ac_var' has changed since the previous run:], 2)
+         AS_MESSAGE([error: '$ac_var' has changed since the previous run:], 2)
          ac_cache_corrupted=:
        else
-         AS_MESSAGE([warning: ignoring whitespace changes in `$ac_var' since 
the previous run:], 2)
+         AS_MESSAGE([warning: ignoring whitespace changes in '$ac_var' since 
the previous run:], 2)
          eval $ac_var=\$ac_old_val
        fi
-       AS_MESSAGE([  former value:  `$ac_old_val'], 2)
-       AS_MESSAGE([  current value: `$ac_new_val'], 2)
+       AS_MESSAGE([  former value:  '$ac_old_val'], 2)
+       AS_MESSAGE([  current value: '$ac_new_val'], 2)
       fi;;
   esac
   # Pass precious variables to config.status.
@@ -1686,9 +1686,9 @@ for ac_var in $ac_precious_vars; do
   fi
 done
 if $ac_cache_corrupted; then
-  AS_MESSAGE([error: in `$ac_pwd':], 2)
+  AS_MESSAGE([error: in '$ac_pwd':], 2)
   AS_MESSAGE([error: changes in the environment can compromise the build], 2)
-  AS_ERROR([run `${MAKE-make} distclean' and/or `rm $cache_file'
+  AS_ERROR([run '${MAKE-make} distclean' and/or 'rm $cache_file'
            and start over])
 fi])dnl
 ])# _AC_ARG_VAR_VALIDATE
@@ -1704,8 +1704,8 @@ fi])dnl
 
 # AC_ARG_PROGRAM
 # --------------
-# This macro is expanded only once, to avoid that `foo' ends up being
-# installed as `ggfoo'.
+# This macro is expanded only once, to avoid that 'foo' ends up being
+# installed as 'ggfoo'.
 AC_DEFUN_ONCE([AC_ARG_PROGRAM],
 [dnl Document the options.
 m4_divert_push([HELP_BEGIN])dnl
@@ -1721,7 +1721,7 @@ test "$program_prefix" != NONE &&
 test "$program_suffix" != NONE &&
   program_transform_name="s&\$&$program_suffix&;$program_transform_name"
 # Double any \ or $.
-# By default was `s,x,x', remove it if useless.
+# By default was 's,x,x', remove it if useless.
 [ac_script='s/[\\$]/&&/g;s/;s,x,x,$//']
 program_transform_name=`AS_ECHO(["$program_transform_name"]) | sed 
"$ac_script"`
 ])# AC_ARG_PROGRAM
@@ -2170,14 +2170,14 @@ m4_define([_AC_CACHE_DUMP],
   (set) 2>&1 |
     case $as_nl`(ac_space=' '; set) 2>&1` in #(
     *${as_nl}ac_space=\ *)
-      # `set' does not quote correctly, so add quotes: double-quote
+      # 'set' does not quote correctly, so add quotes: double-quote
       # substitution turns \\\\ into \\, and sed turns \\ into \.
       sed -n \
        ["s/'/'\\\\''/g;
          s/^\\([_$as_cr_alnum]*_cv_[_$as_cr_alnum]*\\)=\\(.*\\)/\\1='\\2'/p"]
       ;; #(
     *)
-      # `set' quotes correctly as required by POSIX, so do not add quotes.
+      # 'set' quotes correctly as required by POSIX, so do not add quotes.
       sed -n ["/^[_$as_cr_alnum]*_cv_[_$as_cr_alnum]*=/p"]
       ;;
     esac |
@@ -2201,8 +2201,8 @@ m4_define([AC_CACHE_SAVE],
 # config.status only pays attention to the cache file if you give it
 # the --recheck option to rerun configure.
 #
-# `ac_cv_env_foo' variables (set or unset) will be overridden when
-# loading this file, other *unset* `ac_cv_foo' will be assigned the
+# 'ac_cv_env_foo' variables (set or unset) will be overridden when
+# loading this file, other *unset* 'ac_cv_foo' will be assigned the
 # following values.
 
 _ACEOF
@@ -2244,7 +2244,7 @@ rm -f confcache[]dnl
 
 # AC_CACHE_VAL(CACHE-ID, COMMANDS-TO-SET-IT)
 # ------------------------------------------
-# The name of shell var CACHE-ID must contain `_cv_' in order to get saved.
+# The name of shell var CACHE-ID must contain '_cv_' in order to get saved.
 # Should be dnl'ed.  Try to catch common mistakes.
 m4_defun([AC_CACHE_VAL],
 [AS_LITERAL_WORD_IF([$1], [m4_if(m4_index(m4_quote($1), [_cv_]), [-1],
@@ -2367,7 +2367,7 @@ m4_define([_AC_DEFINE_Q],
        [m4_bregexp([[$3]], [[^\\]
 ], [-])], [], [],
        [m4_warn([syntax], [AC_DEFINE]m4_if([$1], [_AC_DEFINE], [],
-  [[_UNQUOTED]])[: `$3' is not a valid preprocessor define value])])]dnl
+  [[_UNQUOTED]])[: '$3' is not a valid preprocessor define value])])]dnl
 [m4_ifval([$4], [AH_TEMPLATE(AC_name, [$4])
 ])_m4_popdef([AC_name])]dnl
 [$1(m4_expand([[@%:@define] $2 ]m4_if([$#], 2, 1,
@@ -2390,12 +2390,12 @@ m4_define([AC_SUBST_TRACE])
 # AC_SUBST(VARIABLE, [VALUE])
 # ---------------------------
 # Create an output variable from a shell VARIABLE.  If VALUE is given
-# assign it to VARIABLE.  Use `""' if you want to set VARIABLE to an
+# assign it to VARIABLE.  Use '""' if you want to set VARIABLE to an
 # empty value, not an empty second argument.
 #
 m4_define([AC_SUBST],
 [AS_IDENTIFIER_IF([$1], [],
-  [m4_fatal([$0: `$1' is not a valid shell variable name])])]dnl
+  [m4_fatal([$0: '$1' is not a valid shell variable name])])]dnl
 [AC_SUBST_TRACE([$1])]dnl
 [m4_pattern_allow([^$1$])]dnl
 [m4_ifvaln([$2], [[$1]=$2])[]]dnl
@@ -2435,18 +2435,18 @@ AC_DEFUN([AC_DIAGNOSE], [m4_warn($@)])
 
 AU_DEFUN([AC_FATAL], [[m4_fatal($@)]])
 AC_DEFUN([AC_FATAL], [m4_fatal($@)dnl
-m4_warn([obsolete], [The macro `$0' is obsolete.
+m4_warn([obsolete], [The macro '$0' is obsolete.
 You should run autoupdate.])])
 
 AU_DEFUN([AC_WARNING],  [[m4_warn([syntax], [$1])]])
 AC_DEFUN([AC_WARNING], [m4_warn([syntax], [$1])dnl
-m4_warn([obsolete], [The macro `$0' is obsolete.
+m4_warn([obsolete], [The macro '$0' is obsolete.
 You should run autoupdate.])])
 
 AU_DEFUN([AC_OBSOLETE], [[m4_warn([obsolete], [$1 is obsolete$2])]],
 [if possible, define this macro using AU_DEFUN.])
 AC_DEFUN([AC_OBSOLETE], [m4_warn([obsolete], [$1 is obsolete$2])dnl
-m4_warn([obsolete], [The macro `$0' is obsolete.
+m4_warn([obsolete], [The macro '$0' is obsolete.
 You should run autoupdate.])])
 
 
@@ -2481,9 +2481,9 @@ m4_copy([AS_WARN],    [AC_MSG_WARN])
 m4_copy([AS_MESSAGE], [AC_MSG_NOTICE])
 m4_copy([AS_ERROR],   [AC_MSG_ERROR])
 m4_define([AC_MSG_FAILURE],
-[{ AS_MESSAGE([error: in `$ac_pwd':], 2)
+[{ AS_MESSAGE([error: in '$ac_pwd':], 2)
 AC_MSG_ERROR([$1
-See `config.log' for more details], [$2]); }])
+See 'config.log' for more details], [$2]); }])
 
 
 # _AC_MSG_LOG_CONFTEST
@@ -2588,11 +2588,11 @@ dnl than expanding it.  This is a hack, but it is 
safer, while also
 dnl typically expanding simple substrings like '$CC', which is what we want.
 dnl
 dnl Much of this macro body is quoted, to work around misuses like
-dnl `AC_CHECK_FUNC(sigblock, , AC_CHECK_LIB(bsd, sigblock))',
+dnl 'AC_CHECK_FUNC(sigblock, , AC_CHECK_LIB(bsd, sigblock))',
 dnl which underquotes the 3rd arg and would misbehave if we didn't quote here.
 dnl The "(($ac_try" instead of $ac_try avoids problems with even-worse
 dnl underquoting misuses, such as
-dnl `AC_CHECK_FUNC(foo, , AC_CHECK_LIB(a, foo, , AC_CHECK_LIB(b, foo)))'.
+dnl 'AC_CHECK_FUNC(foo, , AC_CHECK_LIB(a, foo, , AC_CHECK_LIB(b, foo)))'.
 dnl We normally wouldn't bother with this kind of workaround for invalid code
 dnl but this change was put in just before Autoconf 2.60 and we wanted to
 dnl minimize the integration hassle.
@@ -3030,7 +3030,7 @@ AS_VAR_POPDEF([ac_File])dnl
 # to AC_CHECK_FILE based on FILE.
 m4_define([_AC_CHECK_FILES],
 [[$1], [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_$1]), [1],
-  [Define to 1 if you have the file `$1'.])]])
+  [Define to 1 if you have the file '$1'.])]])
 
 
 # AC_CHECK_FILES(FILE..., [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
@@ -3104,7 +3104,7 @@ extern void ac_decl (int, char *);
 # Shell function body for AC_CHECK_DECL.
 # If we are compiling C, just refer to the name of the function, so we
 # don't implicitly declare it.  However, if we are compiling C++,
-# `(void) function_name;' won't work when function_name has more than one
+# '(void) function_name;' won't work when function_name has more than one
 # overload, we need to fabricate a function call.  Fortunately, there is
 # no such thing as an implicit function declaration in C++.
 # If the function is defined as a macro, we cannot verify its signature
@@ -3168,7 +3168,7 @@ m4_define([_AC_CHECK_DECLS],
 [AC_CHECK_DECL([$1], [ac_have_decl=1], [ac_have_decl=0], [$4])]dnl
 [AC_DEFINE_UNQUOTED(AS_TR_CPP(m4_bpatsubst(HAVE_DECL_[$1],[ *(.*])),
   [$ac_have_decl],
-  [Define to 1 if you have the declaration of `$1',
+  [Define to 1 if you have the declaration of '$1',
    and to 0 if you don't.])]dnl
 [m4_ifvaln([$2$3], [AS_IF([test $ac_have_decl = 1], [$2], [$3])])])
 
@@ -3212,7 +3212,7 @@ AC_DEFUN_ONCE([AC_CONFIG_LIBOBJ_DIR],
 
 # AC_LIBSOURCE(FILE-NAME)
 # -----------------------
-# Announce we might need the file `FILE-NAME'.
+# Announce we might need the file 'FILE-NAME'.
 m4_define([AC_LIBSOURCE], [])
 
 
@@ -3225,7 +3225,7 @@ AC_DEFUN([AC_LIBSOURCES],
 
 # _AC_LIBOBJ(FILE-NAME-NOEXT, ACTION-IF-INDIR)
 # --------------------------------------------
-# We need `FILE-NAME-NOEXT.o', save this into `LIBOBJS'.
+# We need 'FILE-NAME-NOEXT.o', save this into 'LIBOBJS'.
 m4_define([_AC_LIBOBJ],
 [case " $LIB@&t@OBJS " in
   *" $1.$ac_objext "* ) ;;
@@ -3236,7 +3236,7 @@ esac
 
 # AC_LIBOBJ(FILE-NAME-NOEXT)
 # --------------------------
-# We need `FILE-NAME-NOEXT.o', save this into `LIBOBJS'.
+# We need 'FILE-NAME-NOEXT.o', save this into 'LIBOBJS'.
 AC_DEFUN([AC_LIBOBJ],
 [_AC_LIBOBJ([$1])]dnl
 [AS_LITERAL_WORD_IF([$1], [AC_LIBSOURCE([$1.c])],
@@ -3352,7 +3352,7 @@ m4_define([_AC_COMPUTE_INT_BODY],
 # ----------------------------------------------------------
 # Store into the shell variable VARIABLE the value of the integer C expression
 # EXPRESSION.  The value should fit in an initializer in a C variable of type
-# `signed long'.  If no PROLOGUE are specified, the default includes are used.
+# 'signed long'.  If no PROLOGUE are specified, the default includes are used.
 # IF-FAILS is evaluated if the value cannot be found (which includes the
 # case of cross-compilation, if EXPRESSION is not computable at compile-time.
 AC_DEFUN([AC_COMPUTE_INT],
diff --git a/lib/autoconf/headers.m4 b/lib/autoconf/headers.m4
index 548f0562..1e3f749c 100644
--- a/lib/autoconf/headers.m4
+++ b/lib/autoconf/headers.m4
@@ -49,7 +49,7 @@
 # This used to check for headers using the preprocessor only, but we
 # have now switched to running a full compilation, so that we learn
 # about the usability of a header instead of its mere presence.
-# The old behavior is still available by specifying `-' as the
+# The old behavior is still available by specifying '-' as the
 # INCLUDES, but this triggers a deprecation warning.
 #
 # The m4_indir allows for fewer expansions of $@.
@@ -115,7 +115,7 @@ m4_define([_AC_CHECK_HEADER_PREPROC_BODY],
 AC_DEFUN([_AC_CHECK_HEADER_PREPROC],
 [m4_warn([obsolete], [Checking for headers with the preprocessor is
 deprecated. Specify prerequisite code to AC_CHECK_HEADER
-instead of using fourth argument `-'. (Many headers need
+instead of using fourth argument '-'. (Many headers need
 no prerequisites. If you truly need to test whether
 something passes the preprocessor but not the compiler,
 use AC_PREPROC_IFELSE.)])]dnl
@@ -142,12 +142,12 @@ AS_VAR_POPDEF([ac_Header])])# _AC_CHECK_HEADER_PREPROC
 #   AU_DEFUN([_AC_CHECK_HEADER_OLD],
 #     [AC_CHECK_HEADER([$1], [$2], [$3], [-])])
 AC_DEFUN([_AC_CHECK_HEADER_OLD],
-[m4_warn([obsolete], [The macro `$0' is obsolete.
+[m4_warn([obsolete], [The macro '$0' is obsolete.
 You should use AC_CHECK_HEADER with a fourth argument.])]dnl
 [_AC_CHECK_HEADER_PREPROC($@)])
 
 AC_DEFUN([_AC_CHECK_HEADER_NEW],
-[m4_warn([obsolete], [The macro `$0' is obsolete.
+[m4_warn([obsolete], [The macro '$0' is obsolete.
 You should use AC_CHECK_HEADER with a fourth argument.])]dnl
 [_AC_CHECK_HEADER_COMPILE($@)])
 
@@ -213,7 +213,7 @@ m4_define([_AC_CHECK_HEADERS_ONE_C],
 # ""), and perform ACTION-IF-FOUND or ACTION-IF-NOT-FOUND for each
 # header.  INCLUDES is as for AC_CHECK_HEADER.  Additionally, make the
 # preprocessor definition HAVE_HEADER_FILE available for each found
-# header.  Either ACTION may include `break' to stop the search.
+# header.  Either ACTION may include 'break' to stop the search.
 AC_DEFUN([AC_CHECK_HEADERS],
 [_$0(m4_validate_w([$1]), [$2], [$3], [$4])])
 
@@ -340,7 +340,7 @@ m4_map_args([_AC_CHECK_HEADER_ONCE],
 # If INCLUDES is empty, expand in default includes, otherwise in
 # INCLUDES.
 # In most cases INCLUDES is not double quoted as it should, and if
-# for instance INCLUDES = `#include <stdio.h>' then unless we force
+# for instance INCLUDES = '#include <stdio.h>' then unless we force
 # a newline, the hash will swallow the closing paren etc. etc.
 # The usual failure.
 # Take no risk: for the newline.
@@ -439,7 +439,7 @@ AC_DEFUN_ONCE([AC_HEADER_ASSERT],
 #                        [ACTION-IF-FOUND], [ACTION-IF-NOT_FOUND])
 # -----------------------------------------------------------------
 # Like AC_CHECK_HEADER, except also make sure that HEADER-FILE
-# defines the type `DIR'.  dirent.h on NextStep 3.2 doesn't.
+# defines the type 'DIR'.  dirent.h on NextStep 3.2 doesn't.
 m4_define([_AC_CHECK_HEADER_DIRENT],
 [AS_VAR_PUSHDEF([ac_Header], [ac_cv_header_dirent_$1])dnl
 AC_CACHE_CHECK([for $1 that defines DIR], [ac_Header],
@@ -460,7 +460,7 @@ AS_VAR_POPDEF([ac_Header])dnl
 # Like _AH_CHECK_HEADER, but tuned to a dirent provider.
 m4_define([_AH_CHECK_HEADER_DIRENT],
 [AH_TEMPLATE(AS_TR_CPP([HAVE_$1]),
-  [Define to 1 if you have the <$1> header file, and it defines `DIR'.])])
+  [Define to 1 if you have the <$1> header file, and it defines 'DIR'.])])
 
 
 # AC_HEADER_DIRENT
@@ -501,12 +501,12 @@ AC_DEFUN([AC_HEADER_MAJOR],
 [AC_CHECK_HEADERS_ONCE([sys/types.h])
 AC_CHECK_HEADER([sys/mkdev.h],
                [AC_DEFINE([MAJOR_IN_MKDEV], [1],
-                          [Define to 1 if `major', `minor', and `makedev' are
+                          [Define to 1 if 'major', 'minor', and 'makedev' are
                            declared in <mkdev.h>.])])
 if test $ac_cv_header_sys_mkdev_h = no; then
   AC_CHECK_HEADER([sys/sysmacros.h],
                  [AC_DEFINE([MAJOR_IN_SYSMACROS], [1],
-                            [Define to 1 if `major', `minor', and `makedev'
+                            [Define to 1 if 'major', 'minor', and 'makedev'
                              are declared in <sysmacros.h>.])])
 fi
 ])# AC_HEADER_MAJOR
@@ -564,7 +564,7 @@ extern char c4[S_ISSOCK (S_IFREG) ? -1 : 1];
 ]])], ac_cv_header_stat_broken=no, ac_cv_header_stat_broken=yes)])
 if test $ac_cv_header_stat_broken = yes; then
   AC_DEFINE(STAT_MACROS_BROKEN, 1,
-           [Define to 1 if the `S_IS*' macros in <sys/stat.h> do not
+           [Define to 1 if the 'S_IS*' macros in <sys/stat.h> do not
             work properly.])
 fi
 ])# AC_HEADER_STAT
@@ -707,7 +707,7 @@ AU_DEFUN([AC_HEADER_STDC],
 AC_CHECK_INCLUDES_DEFAULT
 AC_PROG_EGREP
 ],
- [The preprocessor macro `STDC_HEADERS' is obsolete.
+ [The preprocessor macro 'STDC_HEADERS' is obsolete.
   Except in unusual embedded environments, you can safely include all
   ISO C90 headers unconditionally.])
 
@@ -802,7 +802,7 @@ if test $ac_cv_sys_tiocgwinsz_in_termios_h != yes; then
   _AC_HEADER_TIOCGWINSZ_IN_SYS_IOCTL
   if test $ac_cv_sys_tiocgwinsz_in_sys_ioctl_h = yes; then
     AC_DEFINE(GWINSZ_IN_SYS_IOCTL,1,
-             [Define to 1 if `TIOCGWINSZ' requires <sys/ioctl.h>.])
+             [Define to 1 if 'TIOCGWINSZ' requires <sys/ioctl.h>.])
   fi
 fi
 ])# AC_HEADER_TIOCGWINSZ
@@ -818,7 +818,7 @@ AC_CHECK_INCLUDES_DEFAULT])
 
 # AU::AC_USG
 # ----------
-# Define `USG' if string functions are *not* in strings.h.
+# Define 'USG' if string functions are *not* in strings.h.
 AU_DEFUN([AC_USG],
 [# Obsolete code to be removed.
 AC_MSG_CHECKING([for BSD string and memory functions])
@@ -855,7 +855,7 @@ AU_DEFUN([AC_MEMORY_H],
 AC_CHECK_HEADERS_ONCE([memory.h])
 if test $ac_cv_header_memory_h = yes; then
    AC_DEFINE([NEED_MEMORY_H], [1],
-             [Same as `HAVE_MEMORY_H', don't depend on me.])
+             [Same as 'HAVE_MEMORY_H', don't depend on me.])
 fi
 # End of obsolete code.
 ],
@@ -866,19 +866,19 @@ to check for string.h.])
 
 # AU::AC_DIR_HEADER
 # -----------------
-# Like calling `AC_HEADER_DIRENT' and `AC_FUNC_CLOSEDIR_VOID', but
+# Like calling 'AC_HEADER_DIRENT' and 'AC_FUNC_CLOSEDIR_VOID', but
 # defines a different set of C preprocessor macros to indicate which
 # header file is found.
 AU_DEFUN([AC_DIR_HEADER],
 [AC_HEADER_DIRENT
 AC_FUNC_CLOSEDIR_VOID
 test ac_cv_header_dirent_dirent_h &&
-  AC_DEFINE([DIRENT], 1, [Same as `HAVE_DIRENT_H', don't depend on me.])
+  AC_DEFINE([DIRENT], 1, [Same as 'HAVE_DIRENT_H', don't depend on me.])
 test ac_cv_header_dirent_sys_ndir_h &&
-  AC_DEFINE([SYSNDIR], 1, [Same as `HAVE_SYS_NDIR_H', don't depend on me.])
+  AC_DEFINE([SYSNDIR], 1, [Same as 'HAVE_SYS_NDIR_H', don't depend on me.])
 test ac_cv_header_dirent_sys_dir_h &&
-  AC_DEFINE([SYSDIR], 1, [Same as `HAVE_SYS_DIR_H', don't depend on me.])
+  AC_DEFINE([SYSDIR], 1, [Same as 'HAVE_SYS_DIR_H', don't depend on me.])
 test ac_cv_header_dirent_ndir_h &&
-  AC_DEFINE([NDIR], 1, [Same as `HAVE_NDIR_H', don't depend on me.])],
-[Remove this warning and the four `AC_DEFINE' when you
-adjust your code to use `AC_HEADER_DIRENT'.])
+  AC_DEFINE([NDIR], 1, [Same as 'HAVE_NDIR_H', don't depend on me.])],
+[Remove this warning and the four 'AC_DEFINE' when you
+adjust your code to use 'AC_HEADER_DIRENT'.])
diff --git a/lib/autoconf/lang.m4 b/lib/autoconf/lang.m4
index daa88418..2cf79b6b 100644
--- a/lib/autoconf/lang.m4
+++ b/lib/autoconf/lang.m4
@@ -195,7 +195,7 @@ m4_define([AC_LANG_DEFINE],
 
 # AC_LANG_CONFTEST(BODY)
 # ----------------------
-# Save the BODY in `conftest.$ac_ext'.  Add a trailing new line.
+# Save the BODY in 'conftest.$ac_ext'.  Add a trailing new line.
 AC_DEFUN([AC_LANG_CONFTEST],
 [m4_pushdef([_AC_LANG_DEFINES_PROVIDED],
   [m4_warn([syntax], [$0: no AC_LANG_SOURCE call detected in body])])]dnl
@@ -226,7 +226,7 @@ m4_define([AC_LANG_DEFINES_PROVIDED],
 # AC_LANG_SOURCE(BODY)
 # --------------------
 # Produce a valid source for the current language, which includes the
-# BODY, and as much as possible `confdefs.h'.
+# BODY, and as much as possible 'confdefs.h'.
 AC_DEFUN([AC_LANG_SOURCE],
 [AC_LANG_DEFINES_PROVIDED[]_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])
 
@@ -242,7 +242,7 @@ m4_define([AC_LANG_SOURCE()],
 # -----------------------------------
 # Produce a valid source for the current language.  Prepend the
 # PROLOGUE (typically CPP directives and/or declarations) to an
-# execution the BODY (typically glued inside the `main' function, or
+# execution the BODY (typically glued inside the 'main' function, or
 # equivalent).
 AC_DEFUN([AC_LANG_PROGRAM],
 [AC_LANG_SOURCE([_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])])
@@ -299,7 +299,7 @@ AC_DEFUN([AC_LANG_BOOL_COMPILE_TRY],
 # AC_LANG_INT_SAVE(PROLOGUE, EXPRESSION)
 # --------------------------------------
 # Produce a program that saves the runtime evaluation of the integer
-# EXPRESSION into `conftest.val'.
+# EXPRESSION into 'conftest.val'.
 AC_DEFUN([AC_LANG_INT_SAVE],
 [_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])
 
@@ -321,7 +321,7 @@ m4_define([_AC_CC],
 # Find a compiler for the current LANG.  Be sure to be run before
 # AC_LANG_PREPROC.
 #
-# Note that because we might AC_REQUIRE `AC_LANG_COMPILER(C)' for
+# Note that because we might AC_REQUIRE 'AC_LANG_COMPILER(C)' for
 # instance, the latter must be AC_DEFUN'd, not just define'd.
 m4_define([AC_LANG_COMPILER],
 [AC_BEFORE([AC_LANG_COMPILER(]_AC_LANG[)],
@@ -345,7 +345,7 @@ AC_DEFUN([AC_LANG_COMPILER_REQUIRE],
 # It doesn't seem necessary right now to have a different source
 # according to the current language, since this works fine.  Some day
 # it might be needed.  Nevertheless, pay attention to the fact that
-# the position of `choke me' on the seventh column is meant: otherwise
+# the position of 'choke me' on the seventh column is meant: otherwise
 # some Fortran compilers (e.g., SGI) might consider it's a
 # continuation line, and warn instead of reporting an error.
 m4_define([_AC_LANG_COMPILER_GNU],
@@ -366,7 +366,7 @@ ac_compiler_gnu=$ac_cv_[]_AC_LANG_ABBREV[]_compiler_gnu
 # AC_LANG_PREPROC
 # ---------------
 # Find a preprocessor for the current language.  Note that because we
-# might AC_REQUIRE `AC_LANG_PREPROC(C)' for instance, the latter must
+# might AC_REQUIRE 'AC_LANG_PREPROC(C)' for instance, the latter must
 # be AC_DEFUN'd, not just define'd.  Since the preprocessor depends
 # upon the compiler, look for the compiler.
 m4_define([AC_LANG_PREPROC],
@@ -459,8 +459,8 @@ m4_divert_pop()dnl
 # a .pdb file
 #
 # When the w32 free Borland C++ command line compiler links a program
-# (conftest.exe), it also produces a file named `conftest.tds' in
-# addition to `conftest.obj'.
+# (conftest.exe), it also produces a file named 'conftest.tds' in
+# addition to 'conftest.obj'.
 #
 # - *.bb, *.bbg
 #   Created per object by GCC when given -ftest-coverage.
@@ -508,15 +508,15 @@ AC_DEFUN([AC_OBJEXT],   [])
 #
 # On OpenVMS 7.1 system, the DEC C 5.5 compiler when called through a
 # GNV (gnv.sourceforge.net) cc wrapper, produces the output file named
-# `a_out.exe'.
+# 'a_out.exe'.
 # b.out is created by i960 compilers.
 #
 # Start with the most likely output file names, but:
-# 1) Beware the clever `test -f' on Cygwin, try the DOS-like .exe names
+# 1) Beware the clever 'test -f' on Cygwin, try the DOS-like .exe names
 # before the counterparts without the extension.
-# 2) The algorithm is not robust to junk in `.', hence go to wildcards
+# 2) The algorithm is not robust to junk in '.', hence go to wildcards
 # (conftest.*) only as a last resort.
-# Beware of `expr' that may return `0' or `'.  Since this macro is
+# Beware of 'expr' that may return '0' or ''.  Since this macro is
 # the first one in touch with the compiler, it should also check that
 # it compiles properly.
 #
@@ -545,8 +545,8 @@ done
 rm -f $ac_rmfiles
 
 AS_IF([_AC_DO_VAR(ac_link_default)],
-[# Autoconf-2.13 could set the ac_cv_exeext variable to `no'.
-# So ignore a value of `no', otherwise this would lead to `EXEEXT = no'
+[# Autoconf-2.13 could set the ac_cv_exeext variable to 'no'.
+# So ignore a value of 'no', otherwise this would lead to 'EXEEXT = no'
 # in a Makefile.  We should not override ac_cv_exeext if it was cached,
 # so that the user can short-circuit this test for compilers unknown to
 # Autoconf.
@@ -566,7 +566,7 @@ do
           ac_cv_exeext=`expr "$ac_file" : ['[^.]*\(\..*\)']`
        fi
        # We set ac_cv_exeext here because the later test for it is not
-       # safe: cross compilers may not add the suffix if given an `-o'
+       # safe: cross compilers may not add the suffix if given an '-o'
        # argument, so we may need to know it at that point already.
        # Even if this section looks crufty: it has the advantage of
        # actually working.
@@ -613,7 +613,7 @@ if test "$cross_compiling" != yes; then
        cross_compiling=yes
     else
        AC_MSG_FAILURE([cannot run _AC_LANG compiled programs.
-If you meant to cross compile, use `--host'.], 77)
+If you meant to cross compile, use '--host'.], 77)
     fi
   fi
 fi
@@ -623,15 +623,15 @@ AC_MSG_RESULT([$cross_compiling])
 
 # _AC_COMPILER_EXEEXT_O
 # ---------------------
-# Check for the extension used when `-o foo'.  Try to see if ac_cv_exeext,
+# Check for the extension used when '-o foo'.  Try to see if ac_cv_exeext,
 # as computed by _AC_COMPILER_EXEEXT_DEFAULT is OK.
 m4_define([_AC_COMPILER_EXEEXT_O],
 [AC_MSG_CHECKING([for suffix of executables])
 AS_IF([_AC_DO_VAR(ac_link)],
-[# If both `conftest.exe' and `conftest' are `present' (well, observable)
-# catch `conftest.exe'.  For instance with Cygwin, `ls conftest' will
-# work properly (i.e., refer to `conftest.exe'), while it won't with
-# `rm'.
+[# If both 'conftest.exe' and 'conftest' are 'present' (well, observable)
+# catch 'conftest.exe'.  For instance with Cygwin, 'ls conftest' will
+# work properly (i.e., refer to 'conftest.exe'), while it won't with
+# 'rm'.
 for ac_file in conftest.exe conftest conftest.*; do
   test -f "$ac_file" || continue
   case $ac_file in
@@ -653,15 +653,15 @@ AC_MSG_RESULT([$ac_cv_exeext])
 # executable.  If this is called, the executable extensions will be
 # automatically used by link commands run by the configure script.
 #
-# Note that some compilers (cross or not), strictly obey to `-o foo' while
-# the host requires `foo.exe', so we should not depend upon `-o' to
+# Note that some compilers (cross or not), strictly obey to '-o foo' while
+# the host requires 'foo.exe', so we should not depend upon '-o' to
 # test EXEEXT.  But then, be sure not to destroy user files.
 #
 # Must be run before _AC_COMPILER_OBJEXT because _AC_COMPILER_EXEEXT_DEFAULT
 # checks whether the compiler works.
 #
 # Do not rename this macro; Automake decides whether EXEEXT is used
-# by checking whether `_AC_COMPILER_EXEEXT' has been expanded.
+# by checking whether '_AC_COMPILER_EXEEXT' has been expanded.
 #
 # See _AC_COMPILER_EXEEXT_CROSS for why we need _AC_LANG_IO_PROGRAM.
 AC_DEFUN([_AC_COMPILER_EXEEXT],
@@ -685,13 +685,13 @@ ac_clean_files=$ac_clean_files_save
 
 # _AC_COMPILER_OBJEXT
 # -------------------
-# Check the object extension used by the compiler: typically `.o' or
-# `.obj'.  If this is called, some other behavior will change,
+# Check the object extension used by the compiler: typically '.o' or
+# '.obj'.  If this is called, some other behavior will change,
 # determined by ac_objext.
 #
 # This macro is called by AC_LANG_COMPILER, the latter being required
 # by the AC_COMPILE_IFELSE macros, so use _AC_COMPILE_IFELSE.  And in fact,
-# don't, since _AC_COMPILE_IFELSE needs to know ac_objext for the `test -s'
+# don't, since _AC_COMPILE_IFELSE needs to know ac_objext for the 'test -s'
 # it includes.  So do it by hand.
 m4_define([_AC_COMPILER_OBJEXT],
 [AC_CACHE_CHECK([for suffix of object files], ac_cv_objext,
diff --git a/lib/autoconf/libs.m4 b/lib/autoconf/libs.m4
index 901c9733..4b2c9a1a 100644
--- a/lib/autoconf/libs.m4
+++ b/lib/autoconf/libs.m4
@@ -92,10 +92,10 @@ AS_VAR_POPDEF([ac_Search])dnl
 # whatever the FUNCTION, in addition to not being a *S macro.  Note
 # that the cache does depend upon the function we are looking for.
 #
-# It is on purpose we used `ac_check_lib_save_LIBS' and not just
-# `ac_save_LIBS': there are many macros which don't want to see `LIBS'
-# changed but still want to use AC_CHECK_LIB, so they save `LIBS'.
-# And ``ac_save_LIBS' is too tempting a name, so let's leave them some
+# It is on purpose we used 'ac_check_lib_save_LIBS' and not just
+# 'ac_save_LIBS': there are many macros which don't want to see 'LIBS'
+# changed but still want to use AC_CHECK_LIB, so they save 'LIBS'.
+# And 'ac_save_LIBS' is too tempting a name, so let's leave them some
 # freedom.
 AC_DEFUN([AC_CHECK_LIB],
 [m4_ifval([$3], , [AH_CHECK_LIB([$1])])dnl
@@ -122,7 +122,7 @@ AS_VAR_POPDEF([ac_Lib])dnl
 # ---------------------
 m4_define([AH_CHECK_LIB],
 [AH_TEMPLATE(AS_TR_CPP([HAVE_LIB$1]),
-            [Define to 1 if you have the `$1' library (-l$1).])])
+            [Define to 1 if you have the '$1' library (-l$1).])])
 
 
 # AC_HAVE_LIBRARY(LIBRARY,
@@ -130,10 +130,10 @@ m4_define([AH_CHECK_LIB],
 #                 [OTHER-LIBRARIES])
 # ---------------------------------------------------------
 #
-# This macro is equivalent to calling `AC_CHECK_LIB' with a FUNCTION
-# argument of `main'.  In addition, LIBRARY can be written as any of
-# `foo', `-lfoo', or `libfoo.a'.  In all of those cases, the compiler
-# is passed `-lfoo'.  However, LIBRARY cannot be a shell variable;
+# This macro is equivalent to calling 'AC_CHECK_LIB' with a FUNCTION
+# argument of 'main'.  In addition, LIBRARY can be written as any of
+# 'foo', '-lfoo', or 'libfoo.a'.  In all of those cases, the compiler
+# is passed '-lfoo'.  However, LIBRARY cannot be a shell variable;
 # it must be a literal name.
 AU_DEFUN([AC_HAVE_LIBRARY],
 [m4_pushdef([AC_Lib_Name],
@@ -344,7 +344,7 @@ X features:
 AC_MSG_CHECKING([for X])
 
 AC_ARG_WITH(x, [  --with-x                use the X Window System])
-# $have_x is `yes', `no', `disabled', or empty when we do not yet know.
+# $have_x is 'yes', 'no', 'disabled', or empty when we do not yet know.
 if test "x$with_x" = xno; then
   # The user explicitly disabled X.
   have_x=disabled
diff --git a/lib/autoconf/programs.m4 b/lib/autoconf/programs.m4
index 588a7bdc..a899218f 100644
--- a/lib/autoconf/programs.m4
+++ b/lib/autoconf/programs.m4
@@ -615,33 +615,33 @@ AC_SUBST(INSTALL_DATA)dnl
 
 # AC_PROG_MKDIR_P
 # ---------------
-# Check whether `mkdir -p' is known to be race-free, and fall back to
+# Check whether 'mkdir -p' is known to be race-free, and fall back to
 # install-sh -d otherwise.
 #
-# Automake 1.8 used `mkdir -m 0755 -p --' to ensure that directories
-# created by `make install' are always world readable, even if the
+# Automake 1.8 used 'mkdir -m 0755 -p --' to ensure that directories
+# created by 'make install' are always world readable, even if the
 # installer happens to have an overly restrictive umask (e.g. 077).
 # This was a mistake.  There are at least two reasons why we must not
-# use `-m 0755':
+# use '-m 0755':
 #   - it causes special bits like SGID to be ignored,
 #   - it may be too restrictive (some setups expect 775 directories).
 #
 # Do not use -m 0755 and let people choose whatever they expect by
 # setting umask.
 #
-# We cannot accept any implementation of `mkdir' that recognizes `-p'.
+# We cannot accept any implementation of 'mkdir' that recognizes '-p'.
 # Some implementations (such as Solaris 8's) are vulnerable to race conditions:
-# if a parallel make tries to run `mkdir -p a/b' and `mkdir -p a/c'
+# if a parallel make tries to run 'mkdir -p a/b' and 'mkdir -p a/c'
 # concurrently, both version can detect that a/ is missing, but only
 # one can create it and the other will error out.  Consequently we
 # restrict ourselves to known race-free implementations.
 #
-# Automake used to define mkdir_p as `mkdir -p .', in order to
+# Automake used to define mkdir_p as 'mkdir -p .', in order to
 # allow $(mkdir_p) to be used without argument.  As in
 #   $(mkdir_p) $(somedir)
 # where $(somedir) is conditionally defined.  However we don't do
 # that for MKDIR_P.
-#  1. before we restricted the check to GNU mkdir, `mkdir -p .' was
+#  1. before we restricted the check to GNU mkdir, 'mkdir -p .' was
 #     reported to fail in read-only directories.  The system where this
 #     happened has been forgotten.
 #  2. in practice we call $(MKDIR_P) on directories such as
@@ -652,11 +652,11 @@ AC_SUBST(INSTALL_DATA)dnl
 #     so $(MKDIR_P) always has an argument.
 #     We will have better chances of detecting a missing test if
 #     $(MKDIR_P) complains about missing arguments.
-#  3. $(MKDIR_P) is named after `mkdir -p' and we don't expect this
+#  3. $(MKDIR_P) is named after 'mkdir -p' and we don't expect this
 #     to accept no argument.
-#  4. having something like `mkdir .' in the output is unsightly.
+#  4. having something like 'mkdir .' in the output is unsightly.
 #
-# On NextStep and OpenStep, the `mkdir' command does not
+# On NextStep and OpenStep, the 'mkdir' command does not
 # recognize any option.  It will interpret all options as
 # directories to create.
 AN_MAKEVAR([MKDIR_P], [AC_PROG_MKDIR_P])
@@ -820,9 +820,9 @@ AS_VAR_SET_IF([LEXLIB], [], [
         [LEXLIB=''],
        [LEXLIB=$ac_cv_lib_lex])
 dnl
-dnl For compatibility with autoconf 2.69 and prior, if $1 is not `noyywrap',
+dnl For compatibility with autoconf 2.69 and prior, if $1 is not 'noyywrap',
 dnl and we didn't already set LEXLIB to -ll or -lfl, see if one of those
-dnl libraries provides yywrap and set LEXLIB to it if so.  If $1 is `yywrap',
+dnl libraries provides yywrap and set LEXLIB to it if so.  If $1 is 'yywrap',
 dnl and we don't find a library that provides yywrap, we fail.
   m4_case([$1],
     [noyywrap],
@@ -866,8 +866,8 @@ AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED
 dnl
 if test $ac_cv_prog_lex_yytext_pointer = yes; then
   AC_DEFINE(YYTEXT_POINTER, 1,
-           [Define to 1 if `lex' declares `yytext' as a `char *' by default,
-            not a `char[]'.])
+           [Define to 1 if 'lex' declares 'yytext' as a 'char *' by default,
+            not a 'char[]'.])
 fi
 ])
 rm -f conftest.l $LEX_OUTPUT_ROOT.c
@@ -897,8 +897,8 @@ fi
 # ----------------
 # Define SET_MAKE to set ${MAKE} if Make does not do so automatically.  If Make
 # does not run the test Makefile, we assume that the Make program the user will
-# invoke does set $(MAKE).  This is typical, and emitting `MAKE=foomake' is
-# always wrong if `foomake' is not available or does not work.
+# invoke does set $(MAKE).  This is typical, and emitting 'MAKE=foomake' is
+# always wrong if 'foomake' is not available or does not work.
 AN_MAKEVAR([MAKE], [AC_PROG_MAKE_SET])
 AN_PROGRAM([make], [AC_PROG_MAKE_SET])
 AC_DEFUN([AC_PROG_MAKE_SET],
@@ -980,9 +980,9 @@ AN_PROGRAM([bison], [AC_PROG_YACC])
 AC_DEFUN([AC_PROG_YACC],
 [AC_CHECK_PROGS(YACC, 'bison -y' byacc, yacc)dnl
 AC_ARG_VAR(YACC,
-[The `Yet Another Compiler Compiler' implementation to use.  Defaults to
-the first program found out of: `bison -y', `byacc', `yacc'.])dnl
+[The 'Yet Another Compiler Compiler' implementation to use.  Defaults to
+the first program found out of: 'bison -y', 'byacc', 'yacc'.])dnl
 AC_ARG_VAR(YFLAGS,
 [The list of arguments that will be passed by default to $YACC.  This script
-will default YFLAGS to the empty string to avoid a default value of `-d' given
+will default YFLAGS to the empty string to avoid a default value of '-d' given
 by some make applications.])])
diff --git a/lib/autoconf/specific.m4 b/lib/autoconf/specific.m4
index 2752e05d..3e61b953 100644
--- a/lib/autoconf/specific.m4
+++ b/lib/autoconf/specific.m4
@@ -180,12 +180,12 @@ fi
 # Security: use a temporary directory as the most portable way of
 # creating files in /tmp securely.  Removing them leaves a race
 # condition, set -C is not portably guaranteed to use O_EXCL, so still
-# leaves a race, and not all systems have the `mktemp' utility.  We
+# leaves a race, and not all systems have the 'mktemp' utility.  We
 # still test for existence first in case of broken systems where the
 # mkdir succeeds even when the directory exists.  Broken systems may
 # retain a race, but they probably have other security problems
 # anyway; this should be secure on well-behaved systems.  In any case,
-# use of `mktemp' is probably inappropriate here since it would fail in
+# use of 'mktemp' is probably inappropriate here since it would fail in
 # attempting to create different file names differing after the 14th
 # character on file systems without long file names.
 AC_DEFUN([AC_SYS_LONG_FILE_NAMES],
@@ -226,11 +226,11 @@ fi
 # AC_SYS_RESTARTABLE_SYSCALLS
 # ---------------------------
 # If the system automatically restarts a system call that is
-# interrupted by a signal, define `HAVE_RESTARTABLE_SYSCALLS'.
+# interrupted by a signal, define 'HAVE_RESTARTABLE_SYSCALLS'.
 AC_DEFUN([AC_SYS_RESTARTABLE_SYSCALLS],
 [m4_warn([obsolete],
 [$0: AC_SYS_RESTARTABLE_SYSCALLS is useful only when supporting very
-old systems that lack `sigaction' and `SA_RESTART'.  Don't bother with
+old systems that lack 'sigaction' and 'SA_RESTART'.  Don't bother with
 this macro unless you need to support very old systems like 4.2BSD and
 SVR3.])dnl
 AC_REQUIRE([AC_HEADER_SYS_WAIT])dnl
@@ -564,7 +564,7 @@ AC_EGREP_CPP([yes],
 AC_HEADER_DIRENT[]dnl
 ],
 [You shouldn't need to depend upon XENIX.  Remove the
-`AC_MSG_CHECKING', `AC_EGREP_CPP', and this warning if this part
+'AC_MSG_CHECKING', 'AC_EGREP_CPP', and this warning if this part
 of the test is useless.])
 
 
diff --git a/lib/autoconf/status.m4 b/lib/autoconf/status.m4
index ca8cb692..c2721a85 100644
--- a/lib/autoconf/status.m4
+++ b/lib/autoconf/status.m4
@@ -30,25 +30,25 @@
 
 
 # This file handles about all the preparation aspects for
-# `config.status': registering the configuration files, the headers,
-# the links, and the commands `config.status' will run.  There is a
-# little mixture though of things actually handled by `configure',
-# such as running the `configure' in the sub directories.  Minor
+# 'config.status': registering the configuration files, the headers,
+# the links, and the commands 'config.status' will run.  There is a
+# little mixture though of things actually handled by 'configure',
+# such as running the 'configure' in the sub directories.  Minor
 # detail.
 #
 # There are two kinds of commands:
 #
 # COMMANDS:
 #
-#   They are output into `config.status' via a quoted here doc.  These
+#   They are output into 'config.status' via a quoted here doc.  These
 #   commands are always associated to a tag which the user can use to
-#   tell `config.status' what are the commands she wants to run.
+#   tell 'config.status' what are the commands she wants to run.
 #
 # INIT-CMDS:
 #
 #   They are output via an *unquoted* here-doc.  As a consequence $var
 #   will be output as the value of VAR.  This is typically used by
-#   `configure' to give `config.status' some variables it needs to run
+#   'configure' to give 'config.status' some variables it needs to run
 #   the COMMANDS.  At the difference of COMMANDS, the INIT-CMDS are
 #   always run.
 #
@@ -68,18 +68,18 @@
 # _AC_SRCDIRS(BUILD-DIR-NAME)
 # ---------------------------
 # Inputs:
-#   - BUILD-DIR-NAME is `top-build -> build' and `top-src -> src'
-#   - `$srcdir' is `top-build -> top-src'
+#   - BUILD-DIR-NAME is 'top-build -> build' and 'top-src -> src'
+#   - '$srcdir' is 'top-build -> top-src'
 #
 # Outputs:
-# - `ac_builddir' is `.', for symmetry only.
-# - `ac_top_builddir_sub' is `build -> top_build'.
+# - 'ac_builddir' is '.', for symmetry only.
+# - 'ac_top_builddir_sub' is 'build -> top_build'.
 #      This is used for @top_builddir@.
-# - `ac_top_build_prefix' is `build -> top_build'.
+# - 'ac_top_build_prefix' is 'build -> top_build'.
 #      If not empty, has a trailing slash.
-# - `ac_srcdir' is `build -> src'.
-# - `ac_top_srcdir' is `build -> top-src'.
-# and `ac_abs_builddir' etc., the absolute directory names.
+# - 'ac_srcdir' is 'build -> src'.
+# - 'ac_top_srcdir' is 'build -> top-src'.
+# and 'ac_abs_builddir' etc., the absolute directory names.
 m4_define([_AC_SRCDIRS],
 [ac_builddir=.
 
@@ -132,8 +132,8 @@ AC_DEFUN([_AC_HAVE_TOP_BUILD_PREFIX])
 # -----------------------------------------
 #
 # Register INIT-COMMANDS as command pasted *unquoted* in
-# `config.status'.  This is typically used to pass variables from
-# `configure' to `config.status'.  Note that $[1] is not over quoted as
+# 'config.status'.  This is typically used to pass variables from
+# 'configure' to 'config.status'.  Note that $[1] is not over quoted as
 # was the case in AC_OUTPUT_COMMANDS.
 m4_define([_AC_CONFIG_COMMANDS_INIT],
 [m4_ifval([$1],
@@ -144,7 +144,7 @@ m4_define([_AC_CONFIG_COMMANDS_INIT],
 
 # AC_FILE_DEPENDENCY_TRACE(DEST, SOURCE1, [SOURCE2...])
 # -----------------------------------------------------
-# This macro does nothing, it's a hook to be read with `autoconf --trace'.
+# This macro does nothing, it's a hook to be read with 'autoconf --trace'.
 #
 # It announces DEST depends upon the SOURCE1 etc.
 m4_define([AC_FILE_DEPENDENCY_TRACE], [])
@@ -160,10 +160,10 @@ m4_define([_AC_FILE_DEPENDENCY_TRACE_COLON],
 
 # _AC_CONFIG_DEPENDENCY(MODE, DEST[:SOURCE1...])
 # ----------------------------------------------
-# MODE is `FILES', `HEADERS', or `LINKS'.
+# MODE is 'FILES', 'HEADERS', or 'LINKS'.
 #
 # Be sure that a missing dependency is expressed as a dependency upon
-# `DEST.in' (except with config links).
+# 'DEST.in' (except with config links).
 #
 m4_define([_AC_CONFIG_DEPENDENCY],
 [_AC_FILE_DEPENDENCY_TRACE_COLON([$2]_AC_CONFIG_DEPENDENCY_DEFAULT($@))dnl
@@ -172,11 +172,11 @@ m4_define([_AC_CONFIG_DEPENDENCY],
 
 # _AC_CONFIG_DEPENDENCY_DEFAULT(MODE, DEST[:SOURCE1...])
 # ------------------------------------------------------
-# Expand to `:DEST.in' if appropriate, or to empty string otherwise.
+# Expand to ':DEST.in' if appropriate, or to empty string otherwise.
 #
 # More detailed description:
-# If the tag contains `:', expand to nothing.
-# Otherwise, for a config file or header, add `:DEST.in'.
+# If the tag contains ':', expand to nothing.
+# Otherwise, for a config file or header, add ':DEST.in'.
 # For a config link, DEST.in is not appropriate:
 #  - if the tag is literal, complain.
 #  - otherwise, just expand to nothing and proceed with fingers crossed.
@@ -186,19 +186,19 @@ m4_define([_AC_CONFIG_DEPENDENCY_DEFAULT],
 [m4_if(m4_index([$2], [:]), [-1],
           [m4_if([$1], [LINKS],
                  [AS_LITERAL_IF([$2],
-                   [m4_fatal([Invalid AC_CONFIG_LINKS tag: `$2'])])],
+                   [m4_fatal([Invalid AC_CONFIG_LINKS tag: '$2'])])],
                  [:$2.in])])])
 
 
 # _AC_CONFIG_UNIQUE(MODE, DEST)
 # -----------------------------
-# MODE is `FILES', `HEADERS', `LINKS', `COMMANDS', or `SUBDIRS'.
+# MODE is 'FILES', 'HEADERS', 'LINKS', 'COMMANDS', or 'SUBDIRS'.
 #
 # Verify that there is no double definition of an output file.
 #
 m4_define([_AC_CONFIG_UNIQUE],
 [m4_ifdef([_AC_SEEN_TAG($2)],
-   [m4_fatal([`$2' is already registered with AC_CONFIG_]m4_defn(
+   [m4_fatal(['$2' is already registered with AC_CONFIG_]m4_defn(
      [_AC_SEEN_TAG($2)]).)],
    [m4_define([_AC_SEEN_TAG($2)], [$1])])dnl
 ])
@@ -206,7 +206,7 @@ m4_define([_AC_CONFIG_UNIQUE],
 
 # _AC_CONFIG_FOOS(MODE, TAGS..., [COMMANDS], [INIT-CMDS])
 # -------------------------------------------------------
-# MODE is `FILES', `HEADERS', `LINKS', or `COMMANDS'.
+# MODE is 'FILES', 'HEADERS', 'LINKS', or 'COMMANDS'.
 #
 # Associate the COMMANDS to each TAG, i.e., when config.status creates TAG,
 # run COMMANDS afterwards.  (This is done in _AC_CONFIG_REGISTER_DEST.)
@@ -233,7 +233,7 @@ m4_define([_AC_CONFIG_COMPUTE_DEST],
 
 # _AC_CONFIG_REGISTER(MODE, TAG, [COMMANDS])
 # ------------------------------------------
-# MODE is `FILES', `HEADERS', `LINKS', or `COMMANDS'.
+# MODE is 'FILES', 'HEADERS', 'LINKS', or 'COMMANDS'.
 #
 m4_define([_AC_CONFIG_REGISTER],
 [m4_if([$1], [COMMANDS],
@@ -245,19 +245,19 @@ m4_define([_AC_CONFIG_REGISTER],
 
 # _AC_CONFIG_REGISTER_DEST(MODE, TAG, DEST, [COMMANDS])
 # -----------------------------------------------------
-# MODE is `FILES', `HEADERS', `LINKS', or `COMMANDS'.
+# MODE is 'FILES', 'HEADERS', 'LINKS', or 'COMMANDS'.
 # TAG is in the form DEST[:SOURCE...].
 # Thus parameter $3 is the first part of $2.
 #
 # With CONFIG_LINKS, reject DEST=., because it is makes it hard for 
./config.status
-# to guess the links to establish (`./config.status .').
+# to guess the links to establish ('./config.status .').
 #
 # Save the name of the first config header to AH_HEADER.
 #
 m4_define([_AC_CONFIG_REGISTER_DEST],
 [_AC_CONFIG_UNIQUE([$1], [$3])]dnl
 [m4_if([$1 $3], [LINKS .],
-       [m4_fatal([invalid destination of a config link: `.'])],
+       [m4_fatal([invalid destination of a config link: '.'])],
        [$1], [HEADERS],
        [m4_define_default([AH_HEADER], [$3])])]dnl
 dnl
@@ -327,7 +327,7 @@ m4_define([_AC_AWK_LITERAL_LIMIT],
 m4_define([_AC_OUTPUT_FILES_PREPARE],
 [# Set up the scripts for CONFIG_FILES section.
 # No need to generate them if there are no CONFIG_FILES.
-# This happens for instance with `./config.status config.h'.
+# This happens for instance with './config.status config.h'.
 if test -n "$CONFIG_FILES"; then
 
 dnl For AC_SUBST_FILE, check for usable getline support in awk,
@@ -351,7 +351,7 @@ else
       print "|#_!!_#|"
       print "cat " F[key] " &&"
       '$ac_cs_awk_pipe_init
-  # The final `:' finishes the AND list.
+  # The final ':' finishes the AND list.
   ac_cs_awk_pipe_fini='END { print "|#_!!_#|"; print ":" }'
 fi]])
 ac_cr=`echo X | tr X '\015'`
@@ -422,8 +422,8 @@ rm -f conf$$subs.sh
 
 dnl Initialize an awk array of substitutions, keyed by variable name.
 dnl
-dnl The initial line contains the variable name VAR, then a `!'.
-dnl Construct `S["VAR"]=' from it.
+dnl The initial line contains the variable name VAR, then a '!'.
+dnl Construct 'S["VAR"]=' from it.
 dnl The rest of the line, and potentially further lines, contain the
 dnl substituted value; the last of those ends with $ac_delim.  We split
 dnl the output both along those substituted newlines and at intervals of
@@ -437,13 +437,13 @@ dnl splitting before the quoting of awk special 
characters (otherwise we
 dnl risk splitting an escape sequence).
 dnl
 dnl Output as separate string literals, joined with backslash-newline.
-dnl Eliminate the newline after `=' in a second script, for readability.
+dnl Eliminate the newline after '=' in a second script, for readability.
 dnl
 dnl Notes to the main part of the awk script:
 dnl - the unusual FS value helps prevent running into the limit of 99 fields,
 dnl - we avoid sub/gsub because of the \& quoting issues, see
 dnl   https://www.gnu.org/software/gawk/manual/html_node/Gory-Details.html
-dnl - Writing `$ 0' prevents expansion by both the shell and m4 here.
+dnl - Writing '$ 0' prevents expansion by both the shell and m4 here.
 dnl
 dnl m4-double-quote most of the scripting for readability.
 [cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
@@ -645,7 +645,7 @@ esac
 _ACEOF
 ])dnl
 
-# Neutralize VPATH when `$srcdir' = `.'.
+# Neutralize VPATH when '$srcdir' = '.'.
 # Shell code in configure.ac might set extrasub.
 # FIXME: do we really want to maintain this feature?
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
@@ -680,7 +680,7 @@ m4_ifndef([AC_DATAROOTDIR_CHECKED],
   { ac_out=`sed -n '/\${datarootdir}/p' "$ac_tmp/out"`; test -n "$ac_out"; } &&
   { ac_out=`sed -n '/^[[        ]]*datarootdir[[        ]]*:*=/p' \
       "$ac_tmp/out"`; test -z "$ac_out"; } &&
-  AC_MSG_WARN([$ac_file contains a reference to the variable `datarootdir'
+  AC_MSG_WARN([$ac_file contains a reference to the variable 'datarootdir'
 which seems to be undefined.  Please make sure it is defined])
 ])dnl
 
@@ -731,14 +731,14 @@ AU_ALIAS([AC_CONFIG_HEADER], [AC_CONFIG_HEADERS])
 m4_define([_AC_OUTPUT_HEADERS_PREPARE],
 [# Set up the scripts for CONFIG_HEADERS section.
 # No need to generate them if there are no CONFIG_HEADERS.
-# This happens for instance with `./config.status Makefile'.
+# This happens for instance with './config.status Makefile'.
 if test -n "$CONFIG_HEADERS"; then
-dnl This `||' list is finished at the end of _AC_OUTPUT_HEADERS_PREPARE.
+dnl This '||' list is finished at the end of _AC_OUTPUT_HEADERS_PREPARE.
 cat >"$ac_tmp/defines.awk" <<\_ACAWK ||
 BEGIN {
 _ACEOF
 
-# Transform confdefs.h into an awk script `defines.awk', embedded as
+# Transform confdefs.h into an awk script 'defines.awk', embedded as
 # here-document in config.status, that substitutes the proper values into
 # config.h.in to produce config.h.
 
@@ -761,9 +761,9 @@ done
 # newline sequences.
 dnl
 dnl Structure of the sed script that reads confdefs.h:
-dnl rset:  main loop, searches for `#define' lines
-dnl def:   deal with a `#define' line
-dnl bsnl:  deal with a `#define' line that ends with backslash-newline
+dnl rset:  main loop, searches for '#define' lines
+dnl def:   deal with a '#define' line
+dnl bsnl:  deal with a '#define' line that ends with backslash-newline
 dnl cont:  handle a continuation line
 dnl bsnlc: handle a continuation line that ends with backslash-newline
 dnl
@@ -774,7 +774,7 @@ dnl
 dnl Long values are split into several string literals with help of ac_delim.
 dnl Assume nobody uses macro names of nearly 150 bytes length.
 dnl
-dnl The initial replace for `#define' lines inserts a leading space
+dnl The initial replace for '#define' lines inserts a leading space
 dnl in order to ease later matching; otherwise, output lines may be
 dnl repeatedly matched.
 dnl
@@ -856,7 +856,7 @@ cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 _ACAWK
 _ACEOF
 cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
-dnl finish `||' list indicating write error:
+dnl finish '||' list indicating write error:
   AC_MSG_ERROR([could not setup config headers machinery])
 fi # test -n "$CONFIG_HEADERS"
 
@@ -866,8 +866,8 @@ fi # test -n "$CONFIG_HEADERS"
 # _AC_OUTPUT_HEADER
 # -----------------
 #
-# Output the code which instantiates the `config.h' files from their
-# `config.h.in'.
+# Output the code which instantiates the 'config.h' files from their
+# 'config.h.in'.
 #
 # This macro is expanded inside a here document.  If the here document is
 # closed, it has to be reopened with
@@ -915,7 +915,7 @@ m4_ifdef([_AC_AM_CONFIG_HEADER_HOOK],
 # Specify that config.status should establish a (symbolic if possible)
 # link from TOP_SRCDIR/SOURCE to TOP_SRCDIR/DEST.
 # Reject DEST=., because it is makes it hard for ./config.status
-# to guess the links to establish (`./config.status .').
+# to guess the links to establish ('./config.status .').
 #
 AC_DEFUN([AC_CONFIG_LINKS], [_AC_CONFIG_FOOS([LINKS], $@)])
 
@@ -926,9 +926,9 @@ AC_DEFUN([AC_CONFIG_LINKS], [_AC_CONFIG_FOOS([LINKS], $@)])
 # link name in DEST...
 #
 # Unfortunately we can't provide a very good autoupdate service here,
-# since in `AC_LINK_FILES($from, $to)' it is possible that `$from'
-# and `$to' are actually lists.  It would then be completely wrong to
-# replace it with `AC_CONFIG_LINKS($to:$from).  It is possible in the
+# since in 'AC_LINK_FILES($from, $to)' it is possible that '$from'
+# and '$to' are actually lists.  It would then be completely wrong to
+# replace it with 'AC_CONFIG_LINKS($to:$from).  It is possible in the
 # case of literal values though, but because I don't think there is any
 # interest in creating config links with literal values, no special
 # mechanism is implemented to handle them.
@@ -948,8 +948,8 @@ while test -n "$ac_sources"; do
 done
 AC_CONFIG_LINKS($[ac_config_links_]_AC_LINK_FILES_CNT)dnl
 ],
-[It is technically impossible to `autoupdate' cleanly from AC_LINK_FILES
-to AC_CONFIG_LINKS.  `autoupdate' provides a functional but inelegant
+[It is technically impossible to 'autoupdate' cleanly from AC_LINK_FILES
+to AC_CONFIG_LINKS.  'autoupdate' provides a functional but inelegant
 update, you should probably tune the result yourself.])# AC_LINK_FILES
 
 
@@ -1015,8 +1015,8 @@ AC_DEFUN([AC_CONFIG_COMMANDS], 
[_AC_CONFIG_FOOS([COMMANDS], $@)])
 #
 # This macro is an obsolete version of AC_CONFIG_COMMANDS.  The only
 # difficulty in mapping AC_OUTPUT_COMMANDS to AC_CONFIG_COMMANDS is
-# to give a unique key.  The scheme we have chosen is `default-1',
-# `default-2' etc. for each call.
+# to give a unique key.  The scheme we have chosen is 'default-1',
+# 'default-2' etc. for each call.
 #
 # Unfortunately this scheme is fragile: bad things might happen
 # if you update an included file and configure.ac: you might have
@@ -1087,7 +1087,7 @@ m4_define([AC_OUTPUT_COMMANDS_POST])
 # - _AC_LIST_SUBDIRS
 #   A statically built list, should contain *all* the arguments of
 #   AC_CONFIG_SUBDIRS.  The final value is assigned to ac_subdirs_all in
-#   the `default' section, and used for --help=recursive.
+#   the 'default' section, and used for --help=recursive.
 #   It makes no sense for arguments which are sh variables.
 # - subdirs
 #   Shell variable built at runtime, so some of these dirs might not be
@@ -1386,7 +1386,7 @@ _ACEOF
 
 cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 ac_cs_usage="\
-\`$as_me' instantiates files and other configuration actions
+'$as_me' instantiates files and other configuration actions
 from templates according to the current configuration.  Unless the files
 and actions are specified as TAGs, all are instantiated by default.
 
@@ -1517,8 +1517,8 @@ m4_ifdef([_AC_SEEN_CONFIG(HEADERS)], [dnl
     ac_need_defaults=false;;
   --he | --h)
     # Conflict between --help and --header
-    AC_MSG_ERROR([ambiguous option: `$[1]'
-Try `$[0] --help' for more information.]);;
+    AC_MSG_ERROR([ambiguous option: '$[1]'
+Try '$[0] --help' for more information.]);;
 ], [  --he | --h |])dnl
   --help | --hel | -h )
     AS_ECHO(["$ac_cs_usage"]); exit ;;
@@ -1527,8 +1527,8 @@ Try `$[0] --help' for more information.]);;
     ac_cs_silent=: ;;
 
   # This is an error.
-  -*) AC_MSG_ERROR([unrecognized option: `$[1]'
-Try `$[0] --help' for more information.]) ;;
+  -*) AC_MSG_ERROR([unrecognized option: '$[1]'
+Try '$[0] --help' for more information.]) ;;
 
   *) AS_VAR_APPEND([ac_config_targets], [" $[1]"])
      ac_need_defaults=false ;;
@@ -1585,7 +1585,7 @@ for ac_config_target in $ac_config_targets
 do
   case $ac_config_target in
 m4_ifdef([_AC_LIST_TAGS], [_AC_LIST_TAGS])
-  *) AC_MSG_ERROR([invalid argument: `$ac_config_target']);;
+  *) AC_MSG_ERROR([invalid argument: '$ac_config_target']);;
   esac
 done
 
@@ -1629,7 +1629,7 @@ fi
 # creating and moving files from /tmp can sometimes cause problems.
 # Hook for its removal unless debugging.
 # Note that there is a small window in which the directory will not be cleaned:
-# after its creation but before its name has been assigned to `$tmp'.
+# after its creation but before its name has been assigned to '$tmp'.
 dnl For historical reasons, AS_TMPDIR must continue to place the results
 dnl in $tmp; but we swap to the namespace-clean $ac_tmp to avoid issues
 dnl with any CONFIG_COMMANDS playing with the common variable name $tmp.
@@ -1663,7 +1663,7 @@ do
   esac
   case $ac_mode$ac_tag in
   :[[FHL]]*:*);;
-  :L* | :C*:*) AC_MSG_ERROR([invalid tag `$ac_tag']);;
+  :L* | :C*:*) AC_MSG_ERROR([invalid tag '$ac_tag']);;
   :[[FH]]-) ac_tag=-:-;;
   :[[FH]]*) ac_tag=$ac_tag:$ac_tag.in;;
   esac
@@ -1685,19 +1685,19 @@ do
       -) ac_f="$ac_tmp/stdin";;
       *) # Look for the file first in the build tree, then in the source tree
         # (if the path is not absolute).  The absolute path cannot be 
DOS-style,
-        # because $ac_f cannot contain `:'.
+        # because $ac_f cannot contain ':'.
         test -f "$ac_f" ||
           case $ac_f in
           [[\\/$]]*) false;;
           *) test -f "$srcdir/$ac_f" && ac_f="$srcdir/$ac_f";;
           esac ||
-          AC_MSG_ERROR([cannot find input file: `$ac_f'], [1]);;
+          AC_MSG_ERROR([cannot find input file: '$ac_f'], [1]);;
       esac
       case $ac_f in *\'*) ac_f=`AS_ECHO(["$ac_f"]) | sed 
"s/'/'\\\\\\\\''/g"`;; esac
       AS_VAR_APPEND([ac_file_inputs], [" '$ac_f'"])
     done
 
-    # Let's still pretend it is `configure' which instantiates (i.e., don't
+    # Let's still pretend it is 'configure' which instantiates (i.e., don't
     # use $as_me), people would be surprised to read:
     #    /* config.h.  Generated by config.status.  */
     configure_input='Generated from '`
diff --git a/lib/autoconf/types.m4 b/lib/autoconf/types.m4
index 87b0ee5f..5f6bbc41 100644
--- a/lib/autoconf/types.m4
+++ b/lib/autoconf/types.m4
@@ -117,10 +117,10 @@
 #
 #        if (sizeof (TYPE))
 #
-# to `read' sizeof (to avoid warnings), while not depending on its type
+# to 'read' sizeof (to avoid warnings), while not depending on its type
 # (not necessarily size_t etc.).
 #
-# C++ disallows defining types inside `sizeof ()', but that's OK,
+# C++ disallows defining types inside 'sizeof ()', but that's OK,
 # since we don't want to consider unnamed structs to be types for C++,
 # precisely because they don't work in cases like that.
 m4_define([_AC_CHECK_TYPE_NEW_BODY],
@@ -167,7 +167,7 @@ AS_VAR_POPDEF([ac_Type])dnl
 # to _AC_CHECK_TYPE_NEW that are based on TYPE.
 m4_define([_AC_CHECK_TYPES],
 [[$1], [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_$1]), [1],
-  [Define to 1 if the system has the type `$1'.])]])
+  [Define to 1 if the system has the type '$1'.])]])
 
 
 # AC_CHECK_TYPES(TYPES,
@@ -189,17 +189,17 @@ $2], [$3], [$4])], [], $1)])
 m4_define([_AC_CHECK_TYPE_OLD],
 [_AC_CHECK_TYPE_NEW([$1],,
    [AC_DEFINE_UNQUOTED([$1], [$2],
-                      [Define to `$2' if <sys/types.h> does not define.])])dnl
+                      [Define to '$2' if <sys/types.h> does not define.])])dnl
 ])# _AC_CHECK_TYPE_OLD
 
 
 # _AC_CHECK_TYPE_REPLACEMENT_TYPE_P(STRING)
 # -----------------------------------------
-# Return `1' if STRING seems to be a builtin C/C++ type, i.e., if it
-# starts with `_Bool', `bool', `char', `double', `float', `int',
-# `long', `short', `signed', or `unsigned' followed by characters
+# Return '1' if STRING seems to be a builtin C/C++ type, i.e., if it
+# starts with '_Bool', 'bool', 'char', 'double', 'float', 'int',
+# 'long', 'short', 'signed', or 'unsigned' followed by characters
 # that are defining types.
-# Because many people have used `off_t' and `size_t' too, they are added
+# Because many people have used 'off_t' and 'size_t' too, they are added
 # for better common-use backward compatibility.
 m4_define([_AC_CHECK_TYPE_REPLACEMENT_TYPE_P],
 [m4_bmatch([$1],
@@ -210,7 +210,7 @@ m4_define([_AC_CHECK_TYPE_REPLACEMENT_TYPE_P],
 
 # _AC_CHECK_TYPE_MAYBE_TYPE_P(STRING)
 # -----------------------------------
-# Return `1' if STRING looks like a C/C++ type.
+# Return '1' if STRING looks like a C/C++ type.
 m4_define([_AC_CHECK_TYPE_MAYBE_TYPE_P],
 [m4_bmatch([$1], [^[_a-zA-Z0-9 ]+\([_a-zA-Z0-9() *]\|\[\|\]\)*$],
          1, 0)dnl
@@ -227,7 +227,7 @@ m4_define([_AC_CHECK_TYPE_MAYBE_TYPE_P],
 # Dispatch respectively to _AC_CHECK_TYPE_OLD or _AC_CHECK_TYPE_NEW.
 # 1. More than two arguments        => NEW
 # 2. $2 seems to be replacement type => OLD
-#    See _AC_CHECK_TYPE_REPLACEMENT_TYPE_P for `replacement type'.
+#    See _AC_CHECK_TYPE_REPLACEMENT_TYPE_P for 'replacement type'.
 # 3. $2 seems to be a type          => NEW plus a warning
 # 4. default                        => NEW
 AC_DEFUN([AC_CHECK_TYPE],
@@ -239,7 +239,7 @@ AC_DEFUN([AC_CHECK_TYPE],
   [_AC_CHECK_TYPE_OLD],
         [_AC_CHECK_TYPE_MAYBE_TYPE_P([$2])], [1],
   [m4_warn([syntax],
-          [$0: assuming `$2' is not a type])_AC_CHECK_TYPE_NEW],
+          [$0: assuming '$2' is not a type])_AC_CHECK_TYPE_NEW],
   [_AC_CHECK_TYPE_NEW])($@)])# AC_CHECK_TYPE
 
 
@@ -296,7 +296,7 @@ if test $ac_cv_type_getgroups = cross; then
 fi])
 AC_DEFINE_UNQUOTED(GETGROUPS_T, $ac_cv_type_getgroups,
                   [Define to the type of elements in the array set by
-                   `getgroups'. Usually this is either `int' or `gid_t'.])
+                   'getgroups'. Usually this is either 'int' or 'gid_t'.])
 ])# AC_TYPE_GETGROUPS
 
 
@@ -313,7 +313,7 @@ AC_DEFUN([AC_TYPE_INTMAX_T],
   AC_REQUIRE([AC_TYPE_LONG_LONG_INT])
   AC_CHECK_TYPE([intmax_t],
     [AC_DEFINE([HAVE_INTMAX_T], 1,
-       [Define to 1 if the system has the type `intmax_t'.])],
+       [Define to 1 if the system has the type 'intmax_t'.])],
     [test $ac_cv_type_long_long_int = yes \
        && ac_type='long long int' \
        || ac_type='long int'
@@ -330,7 +330,7 @@ AC_DEFUN([AC_TYPE_UINTMAX_T],
   AC_REQUIRE([AC_TYPE_UNSIGNED_LONG_LONG_INT])
   AC_CHECK_TYPE([uintmax_t],
     [AC_DEFINE([HAVE_UINTMAX_T], 1,
-       [Define to 1 if the system has the type `uintmax_t'.])],
+       [Define to 1 if the system has the type 'uintmax_t'.])],
     [test $ac_cv_type_unsigned_long_long_int = yes \
        && ac_type='unsigned long long int' \
        || ac_type='unsigned long int'
@@ -346,7 +346,7 @@ AC_DEFUN([AC_TYPE_INTPTR_T],
 [
   AC_CHECK_TYPE([intptr_t],
     [AC_DEFINE([HAVE_INTPTR_T], 1,
-       [Define to 1 if the system has the type `intptr_t'.])],
+       [Define to 1 if the system has the type 'intptr_t'.])],
     [for ac_type in 'int' 'long int' 'long long int'; do
        AC_COMPILE_IFELSE(
         [AC_LANG_BOOL_COMPILE_TRY(
@@ -368,7 +368,7 @@ AC_DEFUN([AC_TYPE_UINTPTR_T],
 [
   AC_CHECK_TYPE([uintptr_t],
     [AC_DEFINE([HAVE_UINTPTR_T], 1,
-       [Define to 1 if the system has the type `uintptr_t'.])],
+       [Define to 1 if the system has the type 'uintptr_t'.])],
     [for ac_type in 'unsigned int' 'unsigned long int' \
        'unsigned long long int'; do
        AC_COMPILE_IFELSE(
@@ -405,7 +405,7 @@ AC_DEFUN([AC_TYPE_LONG_DOUBLE],
      fi])
   if test $ac_cv_type_long_double = yes; then
     AC_DEFINE([HAVE_LONG_DOUBLE], 1,
-      [Define to 1 if the system has the type `long double'.])
+      [Define to 1 if the system has the type 'long double'.])
   fi
 ])
 
@@ -442,8 +442,8 @@ AC_DEFUN([AC_TYPE_LONG_DOUBLE_WIDER],
        ac_cv_type_long_double_wider=no)])
   if test $ac_cv_type_long_double_wider = yes; then
     AC_DEFINE([HAVE_LONG_DOUBLE_WIDER], 1,
-      [Define to 1 if the type `long double' works and has more range or
-       precision than `double'.])
+      [Define to 1 if the type 'long double' works and has more range or
+       precision than 'double'.])
   fi
 ])# AC_TYPE_LONG_DOUBLE_WIDER
 
@@ -456,12 +456,12 @@ AU_DEFUN([AC_C_LONG_DOUBLE],
     ac_cv_c_long_double=$ac_cv_type_long_double_wider
     if test $ac_cv_c_long_double = yes; then
       AC_DEFINE([HAVE_LONG_DOUBLE], 1,
-       [Define to 1 if the type `long double' works and has more range or
-        precision than `double'.])
+       [Define to 1 if the type 'long double' works and has more range or
+        precision than 'double'.])
     fi
   ],
-  [The macro `AC_C_LONG_DOUBLE' is obsolete.
-You should use `AC_TYPE_LONG_DOUBLE' or `AC_TYPE_LONG_DOUBLE_WIDER' instead.]
+  [The macro 'AC_C_LONG_DOUBLE' is obsolete.
+You should use 'AC_TYPE_LONG_DOUBLE' or 'AC_TYPE_LONG_DOUBLE_WIDER' instead.]
 )
 
 
@@ -540,7 +540,7 @@ AC_DEFUN([AC_TYPE_LONG_LONG_INT],
       esac])
   if test $ac_cv_type_long_long_int = yes; then
     AC_DEFINE([HAVE_LONG_LONG_INT], [1],
-      [Define to 1 if the system has the type `long long int'.])
+      [Define to 1 if the system has the type 'long long int'.])
   fi
 ])
 
@@ -562,7 +562,7 @@ AC_DEFUN([AC_TYPE_UNSIGNED_LONG_LONG_INT],
      esac])
   if test $ac_cv_type_unsigned_long_long_int = yes; then
     AC_DEFINE([HAVE_UNSIGNED_LONG_LONG_INT], [1],
-      [Define to 1 if the system has the type `unsigned long long int'.])
+      [Define to 1 if the system has the type 'unsigned long long int'.])
   fi
 ])
 
@@ -597,8 +597,8 @@ AC_DEFUN([AC_TYPE_UID_T],
 [AC_EGREP_HEADER(uid_t, sys/types.h,
   ac_cv_type_uid_t=yes, ac_cv_type_uid_t=no)])
 if test $ac_cv_type_uid_t = no; then
-  AC_DEFINE(uid_t, int, [Define to `int' if <sys/types.h> doesn't define.])
-  AC_DEFINE(gid_t, int, [Define to `int' if <sys/types.h> doesn't define.])
+  AC_DEFINE(uid_t, int, [Define to 'int' if <sys/types.h> doesn't define.])
+  AC_DEFINE(gid_t, int, [Define to 'int' if <sys/types.h> doesn't define.])
 fi
 ])
 
@@ -693,8 +693,8 @@ m4_define([_AC_TYPE_INT_BODY],
 
 # _AC_TYPE_INT(NBITS)
 # -------------------
-# Set a variable ac_cv_c_intNBITS_t to `yes' if intNBITS_t is available,
-# `no' if it is not and no replacement types could be found, and a C type
+# Set a variable ac_cv_c_intNBITS_t to 'yes' if intNBITS_t is available,
+# 'no' if it is not and no replacement types could be found, and a C type
 # if it is not available but a replacement signed integer type of width
 # exactly NBITS bits was found.  In the third case, intNBITS_t is AC_DEFINEd
 # to type, as well.
@@ -740,8 +740,8 @@ m4_define([_AC_TYPE_UNSIGNED_INT_BODY],
 
 # _AC_TYPE_UNSIGNED_INT(NBITS)
 # ----------------------------
-# Set a variable ac_cv_c_uintNBITS_t to `yes' if uintNBITS_t is available,
-# `no' if it is not and no replacement types could be found, and a C type
+# Set a variable ac_cv_c_uintNBITS_t to 'yes' if uintNBITS_t is available,
+# 'no' if it is not and no replacement types could be found, and a C type
 # if it is not available but a replacement unsigned integer type of width
 # exactly NBITS bits was found.  In the third case, uintNBITS_t is AC_DEFINEd
 # to type, as well.
@@ -784,9 +784,9 @@ AU_DEFUN([AC_TYPE_SIGNAL],
                   [ac_cv_type_signal=void])])
 AC_DEFINE_UNQUOTED(RETSIGTYPE, $ac_cv_type_signal,
                   [Define as the return type of signal handlers
-                   (`int' or `void').])
+                   ('int' or 'void').])
 ], [your code may safely assume C89 semantics that RETSIGTYPE is void.
-Remove this warning and the `AC_CACHE_CHECK' when you adjust the code.])
+Remove this warning and the 'AC_CACHE_CHECK' when you adjust the code.])
 
 
 ## ------------------------ ##
@@ -805,7 +805,7 @@ AC_DEFUN([AC_CHECK_SIZEOF],
               [m4_fatal([$0: requires literal arguments])])]dnl
 [# The cast to long int works around a bug in the HP C Compiler
 # version HP92453-01 B.11.11.23709.GP, which incorrectly rejects
-# declarations like `int a3[[(sizeof (unsigned char)) >= 0]];'.
+# declarations like 'int a3[[(sizeof (unsigned char)) >= 0]];'.
 # This bug is HP SR number 8606223364.
 _AC_CACHE_CHECK_INT([size of $1], [AS_TR_SH([ac_cv_sizeof_$1])],
   [(long int) (sizeof ($1))],
@@ -817,7 +817,7 @@ _AC_CACHE_CHECK_INT([size of $1], 
[AS_TR_SH([ac_cv_sizeof_$1])],
    fi])
 
 AC_DEFINE_UNQUOTED(AS_TR_CPP(sizeof_$1), $AS_TR_SH([ac_cv_sizeof_$1]),
-                  [The size of `$1', as computed by sizeof.])
+                  [The size of '$1', as computed by sizeof.])
 ])# AC_CHECK_SIZEOF
 
 
@@ -846,7 +846,7 @@ typedef struct { char x; $1 y; } ac__type_alignof_;],
    fi])
 
 AC_DEFINE_UNQUOTED(AS_TR_CPP(alignof_$3), $AS_TR_SH([ac_cv_alignof_$3]),
-                  [The normal alignment of `$1', in bytes.])
+                  [The normal alignment of '$1', in bytes.])
 ])# AC_CHECK_ALIGNOF
 
 
@@ -857,9 +857,9 @@ AU_DEFUN([AC_INT_16_BITS],
 [AC_CHECK_SIZEOF([int])
 test $ac_cv_sizeof_int = 2 &&
   AC_DEFINE(INT_16_BITS, 1,
-           [Define to 1 if `sizeof (int)' = 2.  Obsolete, use `SIZEOF_INT'.])
-], [your code should no longer depend upon `INT_16_BITS', but upon
-`SIZEOF_INT == 2'.  Remove this warning and the `AC_DEFINE' when you
+           [Define to 1 if 'sizeof (int)' = 2.  Obsolete, use 'SIZEOF_INT'.])
+], [your code should no longer depend upon 'INT_16_BITS', but upon
+'SIZEOF_INT == 2'.  Remove this warning and the 'AC_DEFINE' when you
 adjust the code.])
 
 
@@ -869,10 +869,10 @@ AU_DEFUN([AC_LONG_64_BITS],
 [AC_CHECK_SIZEOF([long int])
 test $ac_cv_sizeof_long_int = 8 &&
   AC_DEFINE(LONG_64_BITS, 1,
-           [Define to 1 if `sizeof (long int)' = 8.  Obsolete, use
-            `SIZEOF_LONG_INT'.])
-], [your code should no longer depend upon `LONG_64_BITS', but upon
-`SIZEOF_LONG_INT == 8'.  Remove this warning and the `AC_DEFINE' when
+           [Define to 1 if 'sizeof (long int)' = 8.  Obsolete, use
+            'SIZEOF_LONG_INT'.])
+], [your code should no longer depend upon 'LONG_64_BITS', but upon
+'SIZEOF_LONG_INT == 8'.  Remove this warning and the 'AC_DEFINE' when
 you adjust the code.])
 
 
@@ -910,7 +910,7 @@ return 0;])],
 #                [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND],
 #                [INCLUDES = DEFAULT-INCLUDES])
 # ---------------------------------------------------------
-# AGGREGATE.MEMBER is for instance `struct passwd.pw_gecos', shell
+# AGGREGATE.MEMBER is for instance 'struct passwd.pw_gecos', shell
 # variables are not a valid argument.
 AC_DEFUN([AC_CHECK_MEMBER],
 [AC_REQUIRE_SHELL_FN([ac_fn_]_AC_LANG_ABBREV[_check_member],
@@ -921,7 +921,7 @@ AC_DEFUN([AC_CHECK_MEMBER],
     [_$0_BODY])]dnl
 [AS_LITERAL_IF([$1], [], [m4_fatal([$0: requires literal arguments])])]dnl
 [m4_if(m4_index([$1], [.]), [-1],
-  [m4_fatal([$0: Did not see any dot in `$1'])])]dnl
+  [m4_fatal([$0: Did not see any dot in '$1'])])]dnl
 [AS_VAR_PUSHDEF([ac_Member], [ac_cv_member_$1])]dnl
 [ac_fn_[]_AC_LANG_ABBREV[]_check_member "$LINENO" ]dnl
 [m4_bpatsubst([$1], [^\([^.]*\)\.\(.*\)], ["\1" "\2"]) "ac_Member" ]dnl
@@ -937,8 +937,8 @@ AS_VAR_POPDEF([ac_Member])dnl
 # arguments to AC_CHECK_MEMBER that are based on AGGREGATE and MEMBER.
 m4_define([_AC_CHECK_MEMBERS],
 [[$1], [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_$1]), [1],
-  [Define to 1 if `]m4_bpatsubst([$1],
-    [^\([^.]*\)\.\(.*\)], [[\2' is a member of `\1]])['.])]])
+  [Define to 1 if ']m4_bpatsubst([$1],
+    [^\([^.]*\)\.\(.*\)], [[\2' is a member of '\1]])['.])]])
 
 # AC_CHECK_MEMBERS([AGGREGATE.MEMBER, ...],
 #                 [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND],
@@ -1000,18 +1000,18 @@ AC_DEFUN([AC_STRUCT_DIRENT_D_TYPE], 
[_AC_STRUCT_DIRENT([d_type])])
 AU_DEFUN([AC_STRUCT_ST_BLKSIZE],
 [AC_CHECK_MEMBERS([struct stat.st_blksize],
                 [AC_DEFINE(HAVE_ST_BLKSIZE, 1,
-                           [Define to 1 if your `struct stat' has
-                            `st_blksize'.  Deprecated, use
-                            `HAVE_STRUCT_STAT_ST_BLKSIZE' instead.])])
-], [your code should no longer depend upon `HAVE_ST_BLKSIZE', but
-`HAVE_STRUCT_STAT_ST_BLKSIZE'.  Remove this warning and
-the `AC_DEFINE' when you adjust the code.])# AC_STRUCT_ST_BLKSIZE
+                           [Define to 1 if your 'struct stat' has
+                            'st_blksize'.  Deprecated, use
+                            'HAVE_STRUCT_STAT_ST_BLKSIZE' instead.])])
+], [your code should no longer depend upon 'HAVE_ST_BLKSIZE', but
+'HAVE_STRUCT_STAT_ST_BLKSIZE'.  Remove this warning and
+the 'AC_DEFINE' when you adjust the code.])# AC_STRUCT_ST_BLKSIZE
 
 
 # AC_STRUCT_ST_BLOCKS
 # -------------------
-# If `struct stat' contains an `st_blocks' member, define
-# HAVE_STRUCT_STAT_ST_BLOCKS.  Otherwise, add `fileblocks.o' to the
+# If 'struct stat' contains an 'st_blocks' member, define
+# HAVE_STRUCT_STAT_ST_BLOCKS.  Otherwise, add 'fileblocks.o' to the
 # output variable LIBOBJS.  We still define HAVE_ST_BLOCKS for backward
 # compatibility.  In the future, we will activate specializations for
 # this macro, so don't obsolete it right now.
@@ -1019,16 +1019,16 @@ the `AC_DEFINE' when you adjust the code.])# 
AC_STRUCT_ST_BLKSIZE
 # AC_OBSOLETE([$0], [; replace it with
 #   AC_CHECK_MEMBERS([struct stat.st_blocks],
 #                    [AC_LIBOBJ([fileblocks])])
-# Please note that it will define `HAVE_STRUCT_STAT_ST_BLOCKS',
-# and not `HAVE_ST_BLOCKS'.])dnl
+# Please note that it will define 'HAVE_STRUCT_STAT_ST_BLOCKS',
+# and not 'HAVE_ST_BLOCKS'.])dnl
 #
 AN_IDENTIFIER([st_blocks],  [AC_STRUCT_ST_BLOCKS])
 AC_DEFUN([AC_STRUCT_ST_BLOCKS],
 [AC_CHECK_MEMBERS([struct stat.st_blocks],
                  [AC_DEFINE(HAVE_ST_BLOCKS, 1,
-                            [Define to 1 if your `struct stat' has
-                             `st_blocks'.  Deprecated, use
-                             `HAVE_STRUCT_STAT_ST_BLOCKS' instead.])],
+                            [Define to 1 if your 'struct stat' has
+                             'st_blocks'.  Deprecated, use
+                             'HAVE_STRUCT_STAT_ST_BLOCKS' instead.])],
                  [AC_LIBOBJ([fileblocks])])
 ])# AC_STRUCT_ST_BLOCKS
 
@@ -1038,12 +1038,12 @@ AC_DEFUN([AC_STRUCT_ST_BLOCKS],
 AU_DEFUN([AC_STRUCT_ST_RDEV],
 [AC_CHECK_MEMBERS([struct stat.st_rdev],
                 [AC_DEFINE(HAVE_ST_RDEV, 1,
-                           [Define to 1 if your `struct stat' has `st_rdev'.
-                            Deprecated, use `HAVE_STRUCT_STAT_ST_RDEV'
+                           [Define to 1 if your 'struct stat' has 'st_rdev'.
+                            Deprecated, use 'HAVE_STRUCT_STAT_ST_RDEV'
                             instead.])])
-], [your code should no longer depend upon `HAVE_ST_RDEV', but
-`HAVE_STRUCT_STAT_ST_RDEV'.  Remove this warning and
-the `AC_DEFINE' when you adjust the code.])# AC_STRUCT_ST_RDEV
+], [your code should no longer depend upon 'HAVE_ST_RDEV', but
+'HAVE_STRUCT_STAT_ST_RDEV'.  Remove this warning and
+the 'AC_DEFINE' when you adjust the code.])# AC_STRUCT_ST_RDEV
 
 
 # AC_STRUCT_TM
@@ -1063,16 +1063,16 @@ AC_DEFUN([AC_STRUCT_TM],
                   [ac_cv_struct_tm=sys/time.h])])
 if test $ac_cv_struct_tm = sys/time.h; then
   AC_DEFINE(TM_IN_SYS_TIME, 1,
-           [Define to 1 if your <sys/time.h> declares `struct tm'.])
+           [Define to 1 if your <sys/time.h> declares 'struct tm'.])
 fi
 ])# AC_STRUCT_TM
 
 
 # AC_STRUCT_TIMEZONE
 # ------------------
-# Figure out how to get the current timezone.  If `struct tm' has a
-# `tm_zone' member, define `HAVE_TM_ZONE'.  Otherwise, if the
-# external array `tzname' is found, define `HAVE_TZNAME'.
+# Figure out how to get the current timezone.  If 'struct tm' has a
+# 'tm_zone' member, define 'HAVE_TM_ZONE'.  Otherwise, if the
+# external array 'tzname' is found, define 'HAVE_TZNAME'.
 AN_IDENTIFIER([tm_zone], [AC_STRUCT_TIMEZONE])
 AC_DEFUN([AC_STRUCT_TIMEZONE],
 [AC_REQUIRE([AC_STRUCT_TM])dnl
@@ -1081,8 +1081,8 @@ AC_CHECK_MEMBERS([struct tm.tm_zone],,,[#include 
<sys/types.h>
 ])
 if test "$ac_cv_member_struct_tm_tm_zone" = yes; then
   AC_DEFINE(HAVE_TM_ZONE, 1,
-           [Define to 1 if your `struct tm' has `tm_zone'. Deprecated, use
-            `HAVE_STRUCT_TM_TM_ZONE' instead.])
+           [Define to 1 if your 'struct tm' has 'tm_zone'. Deprecated, use
+            'HAVE_STRUCT_TM_TM_ZONE' instead.])
 else
   AC_CHECK_DECLS([tzname], , , [#include <time.h>])
   AC_CACHE_CHECK(for tzname, ac_cv_var_tzname,
@@ -1097,8 +1097,8 @@ extern char *tzname[];
                [ac_cv_var_tzname=no])])
   if test $ac_cv_var_tzname = yes; then
     AC_DEFINE(HAVE_TZNAME, 1,
-             [Define to 1 if you don't have `tm_zone' but do have the external
-              array `tzname'.])
+             [Define to 1 if you don't have 'tm_zone' but do have the external
+              array 'tzname'.])
   fi
 fi
 ])# AC_STRUCT_TIMEZONE
diff --git a/lib/autotest/general.m4 b/lib/autotest/general.m4
index 40c92d93..ef8a962b 100644
--- a/lib/autotest/general.m4
+++ b/lib/autotest/general.m4
@@ -30,7 +30,7 @@ Copyright (C) 2000-2017, 2020-2021 Free Software Foundation, 
Inc.
 # Convert a diversion name into its number.  Otherwise, return
 # DIVERSION-NAME which is supposed to be an actual diversion number.
 # Of course it would be nicer to use m4_case here, instead of zillions
-# of little macros, but it then takes twice longer to run `autoconf'!
+# of little macros, but it then takes twice longer to run 'autoconf'!
 #
 # From M4sugar:
 #    -1. KILL
@@ -91,7 +91,7 @@ Copyright (C) 2000-2017, 2020-2021 Free Software Foundation, 
Inc.
 #    The core of the test suite.
 #
 #  - TEST_SCRIPT
-#    The collector for code for each test, the ``normal'' diversion, but
+#    The collector for code for each test, the "normal" diversion, but
 #    undiverted into other locations before final output.
 #
 #  - TEST_GROUPS
@@ -124,7 +124,7 @@ m4_define([_m4_divert(TEST_GROUPS)],        500)
 # -------
 # Return the current file sans directory, a colon, and the current
 # line.  Be sure to return a _quoted_ file name, so if, for instance,
-# the user is lunatic enough to have a file named `dnl' (and I, for
+# the user is lunatic enough to have a file named 'dnl' (and I, for
 # one, love to be brainless and stubborn sometimes), then we return a
 # quoted name.
 #
@@ -132,10 +132,10 @@ m4_define([_m4_divert(TEST_GROUPS)],        500)
 #
 #  m4_bpatsubst(__file__, [^.*/\(.*\)], [[\1]])
 #
-# since then, since `dnl' doesn't match the pattern, it is returned
+# since then, since 'dnl' doesn't match the pattern, it is returned
 # with once quotation level less, so you lose!  And since GNU M4
 # is one of the biggest junk in the whole universe wrt regexp, don't
-# even think about using `?' or `\?'.  Bah, `*' will do.
+# even think about using '?' or '\?'.  Bah, '*' will do.
 # Pleeeeeeeease, Gary, provide us with dirname and ERE!
 #
 # M4 recompiles the regular expression for every m4_bpatsubst, but __file__
@@ -327,7 +327,7 @@ exit code; if it is anything else print an error message 
referring to LINE,
 and fail the test.])
 at_fn_check_status ()
 {
-dnl This order ensures that we don't `skip' if we are precisely checking
+dnl This order ensures that we don't 'skip' if we are precisely checking
 dnl $? = 77 or $? = 99.
   case $[2] in
     $[1] ) ;;
@@ -394,7 +394,7 @@ at_traceon=:
 at_trace_echo=:
 at_check_filter_trace=:
 
-# Shall we keep the debug scripts?  Must be `:' when the suite is
+# Shall we keep the debug scripts?  Must be ':' when the suite is
 # run by a debug script, so that the script doesn't remove itself.
 at_debug_p=false
 # Display help message?
@@ -430,7 +430,7 @@ m4_divert_text([DEFAULTS],
 # Whether to enable colored test results.
 at_color=m4_ifdef([AT_color], [AT_color], [no])
 # As many question marks as there are digits in the last test group number.
-# Used to normalize the test group numbers so that `ls' lists them in
+# Used to normalize the test group numbers so that 'ls' lists them in
 # numerical order.
 at_format='m4_bpatsubst(m4_defn([AT_ordinal]), [.], [?])'
 # Description of all the test groups.
@@ -634,7 +634,7 @@ m4_divert_push([PARSE_ARGS_END])dnl
        # Reject names that are not valid shell variable names.
        case $at_envvar in
          '' | [[0-9]]* | *[[!_$as_cr_alnum]]* )
-           AS_ERROR([invalid variable name: `$at_envvar']) ;;
+           AS_ERROR([invalid variable name: '$at_envvar']) ;;
        esac
        at_value=`AS_ECHO(["$at_optarg"]) | sed "s/'/'\\\\\\\\''/g"`
        # Export now, but save eval for later and for debug scripts.
@@ -643,14 +643,14 @@ m4_divert_push([PARSE_ARGS_END])dnl
        ;;
 
      *) AS_ECHO(["$as_me: invalid option: $at_option"]) >&2
-       AS_ECHO(["Try \`$[0] --help' for more information."]) >&2
+       AS_ECHO(["Try '$[0] --help' for more information."]) >&2
        exit 1
        ;;
   esac
 done
 
 # Verify our last option didn't require an argument
-AS_IF([test -n "$at_prev"], [AS_ERROR([`$at_prev' requires an argument])])
+AS_IF([test -n "$at_prev"], [AS_ERROR(['$at_prev' requires an argument])])
 
 # The file containing the suite.
 at_suite_log=$at_dir/$as_me.log
@@ -697,7 +697,7 @@ Run all the tests, or the selected TESTS, given by numeric 
ranges, and
 save a detailed log file.  Upon failure, create debugging scripts.
 
 Do not change environment variables directly.  Instead, set them via
-command line arguments.  Set \`AUTOTEST_PATH' to select the executables
+command line arguments.  Set 'AUTOTEST_PATH' to select the executables
 to exercise.  Each relative directory is expanded as build and source
 directories relative to the top level of this distribution.
 E.g., from within the build directory /tmp/foo-1.0, invoking this:
@@ -734,7 +734,7 @@ Execution tuning:
 [                 Allow N jobs at once; infinite jobs with no arg (default 1)]
   -k, --keywords=KEYWORDS
 [                 select the tests matching all the comma-separated KEYWORDS]
-[                 multiple \`-k' accumulate; prefixed \`!' negates a KEYWORD]
+[                 multiple '-k' accumulate; prefixed '!' negates a KEYWORD]
       --recheck  select all tests that failed or passed unexpectedly last time
   -e, --errexit  abort as soon as a test fails; implies --debug
   -v, --verbose  force more detailed output
@@ -877,7 +877,7 @@ m4_text_box([Directory structure.])
 # | + ...           - files created during the group
 
 # The directory the whole suite works in.
-# Should be absolute to let the user `cd' at will.
+# Should be absolute to let the user 'cd' at will.
 at_suite_dir=$at_dir/$as_me.dir
 # The file containing the suite ($at_dir might have changed since earlier).
 at_suite_log=$at_dir/$as_me.log
@@ -898,7 +898,7 @@ fi
 # Don't take risks: use only absolute directories in PATH.
 #
 # For stand-alone test suites (ie. atconfig was not found),
-# AUTOTEST_PATH is relative to `.'.
+# AUTOTEST_PATH is relative to '.'.
 #
 # For embedded test suites, AUTOTEST_PATH is relative to the top level
 # of the package.  Then expand it into build/src parts, since users
@@ -948,7 +948,7 @@ dnl The parent needs two fds to the same fifo, otherwise, 
there is a race
 dnl where the parent can read the fifo before a child opens it for writing
 m4_define([AT_JOB_FIFO_IN_FD], [6])
 m4_define([AT_JOB_FIFO_OUT_FD], [7])
-[#] AS_MESSAGE_LOG_FD is the log file.  Not to be overwritten if `-d'.
+[#] AS_MESSAGE_LOG_FD is the log file.  Not to be overwritten if '-d'.
 if $at_debug_p; then
   at_suite_log=/dev/null
 else
@@ -1000,9 +1000,9 @@ AS_ECHO(["$as_me: starting at: $at_start_date"]) 
>&AS_MESSAGE_LOG_FD
 
 # Create the master directory if it doesn't already exist.
 AS_MKDIR_P(["$at_suite_dir"]) ||
-  AS_ERROR([cannot create `$at_suite_dir'])
+  AS_ERROR([cannot create '$at_suite_dir'])
 
-# Can we diff with `/dev/null'?  DU 5.0 refuses.
+# Can we diff with '/dev/null'?  DU 5.0 refuses.
 if diff /dev/null /dev/null >/dev/null 2>&1; then
   at_devnull=/dev/null
 else
@@ -1010,7 +1010,7 @@ else
   >"$at_devnull"
 fi
 
-# Use `diff -u' when possible.
+# Use 'diff -u' when possible.
 if at_diff=`diff -u "$at_devnull" "$at_devnull" 2>&1` && test -z "$at_diff"
 then
   at_diff='diff -u'
@@ -1037,7 +1037,7 @@ BEGIN { FS="" }
   AS_ERROR([cannot create test line number cache])
 rm -f "$at_suite_dir/at-source-lines"
 
-# Set number of jobs for `-j'; avoid more jobs than test groups.
+# Set number of jobs for '-j'; avoid more jobs than test groups.
 set X $at_groups; shift; at_max_jobs=$[@%:@]
 if test $at_max_jobs -eq 0; then
   at_jobs=1
@@ -1101,7 +1101,7 @@ at_fn_group_prepare ()
   at_group_log=$at_group_dir/$as_me.log
   _AS_CLEAN_DIR("$at_group_dir") ||
     AS_WARN([test directory for $at_group_normalized could not be cleaned])
-  # Be tolerant if the above `rm' was not able to remove the directory.
+  # Be tolerant if the above 'rm' was not able to remove the directory.
   AS_MKDIR_P(["$at_group_dir"])
 
   echo 0 > "$at_status_file"
@@ -1138,7 +1138,7 @@ AS_FUNCTION_DESCRIBE([at_fn_group_postprocess], [],
 at_fn_group_postprocess ()
 {
   # Be sure to come back to the suite directory, in particular
-  # since below we might `rm' the group directory we are in currently.
+  # since below we might 'rm' the group directory we are in currently.
   cd "$at_suite_dir"
 
   if test ! -f "$at_check_line_file"; then
@@ -1284,7 +1284,7 @@ dnl Gather process group IDs of currently running jobs.
        for at_pgid in `jobs -p 2>/dev/null`; do
          at_pgids="$at_pgids $at_job_group$at_pgid"
        done
-dnl Ignore `kill' errors, as some jobs may have finished in the meantime.
+dnl Ignore 'kill' errors, as some jobs may have finished in the meantime.
        test -z "$at_pgids" || kill -$at_signal $at_pgids 2>/dev/null
 dnl wait until all jobs have exited.
        wait
@@ -1607,7 +1607,7 @@ else
   if $at_debug_p; then
     at_msg='per-test log files'
   else
-    at_msg="\`${at_testdir+${at_testdir}/}$as_me.log'"
+    at_msg="'${at_testdir+${at_testdir}/}$as_me.log'"
   fi
   at_msg1a=${at_xpass_list:+', '}
   at_msg1=$at_fail_list${at_fail_list:+" failed$at_msg1a"}
@@ -1621,7 +1621,7 @@ $at_msg1$at_msg2
 
 You may investigate any problem if you feel able to do so, in which
 case the test suite provides a good starting point.  Its output may
-be found below \`${at_testdir+${at_testdir}/}$as_me.dir'.
+be found below '${at_testdir+${at_testdir}/}$as_me.dir'.
 "])
   exit 1
 fi
@@ -1722,13 +1722,13 @@ AS_IF([$at_arg_given_[]AT_first_option_tr],,[$5])dnl
 # Add HELP-TEXT to the HELP_OTHER diversion.
 #
 # Leading dashes should not be passed in OPTIONS.  Users will be required
-# to pass `--' before long options and `-' before single character options.
+# to pass '--' before long options and '-' before single character options.
 #
-# $at_arg_OPTION will be set to `:' if this option is received, `false' if
-# if --no-OPTION is received, and `false' by default.
+# $at_arg_OPTION will be set to ':' if this option is received, 'false' if
+# if --no-OPTION is received, and 'false' by default.
 #
 # Run ACTION-IF-GIVEN each time an option in OPTIONS is encountered; here,
-# $at_optarg will be set to `:' or `false' as appropriate.  $at_optarg is
+# $at_optarg will be set to ':' or 'false' as appropriate.  $at_optarg is
 # actually just a copy of $at_arg_OPTION.
 #
 # ACTION-IF-NOT-GIVEN will be run once after option parsing is complete and
@@ -1742,11 +1742,11 @@ 
m4_defun([AT_ARG_OPTION],[_AT_ARG_OPTION([$1],[$2],,[$3],[$4])])
 # first one.  Add HELP-TEXT to the HELP_OTHER diversion.
 #
 # Leading dashes should not be passed in OPTIONS.  Users will be required
-# to pass `--' before long options and `-' before single character options.
+# to pass '--' before long options and '-' before single character options.
 #
 # By default, any argument to these options will be assigned to the shell
 # variable $at_arg_OPTION, where OPTION is the first option in OPTIONS with
-# any `-' characters replaced with `_'.
+# any '-' characters replaced with '_'.
 #
 # Run ACTION-IF-GIVEN each time an option in OPTIONS is encountered; here,
 # $at_optarg will be set to the option argument.  $at_optarg is actually just
@@ -2033,37 +2033,37 @@ $2[]_ATEOF
 # STDERR contents.  Shell metacharacters in STDOUT and STDERR are
 # _not_ processed by the shell, but are treated as string literals.
 #
-# STATUS, STDOUT, and STDERR are not checked if equal to `ignore'.
+# STATUS, STDOUT, and STDERR are not checked if equal to 'ignore'.
 #
-# If STDOUT is `expout', then stdout is compared to the content of the file
-# `expout'.  Likewise for STDERR and `experr'.
+# If STDOUT is 'expout', then stdout is compared to the content of the file
+# 'expout'.  Likewise for STDERR and 'experr'.
 #
-# If STDOUT is `stdout', then the stdout is left in the file `stdout',
-# likewise for STDERR and `stderr'.  Don't do this:
+# If STDOUT is 'stdout', then the stdout is left in the file 'stdout',
+# likewise for STDERR and 'stderr'.  Don't do this:
 #
 #    AT_CHECK([command >out])
-#    # Some checks on `out'
+#    # Some checks on 'out'
 #
 # do this instead:
 #
 #    AT_CHECK([command], [], [stdout])
-#    # Some checks on `stdout'
+#    # Some checks on 'stdout'
 #
-# You might wonder why you can't just use `ignore', then directly use stdout
+# You might wonder why you can't just use 'ignore', then directly use stdout
 # and stderr left by the test suite:
 #
 #    AT_CHECK([command], [], [ignore])
 #    AT_CHECK([check stdout])
 #
-# If the test suite always captured data in the file `stdout', then the
+# If the test suite always captured data in the file 'stdout', then the
 # second command would be trying to read and write from the same file, with
 # undefined behavior.  Therefore, the test suite actually captures data in
-# an internal file of a different name, and only creates `stdout' when
+# an internal file of a different name, and only creates 'stdout' when
 # explicitly requested.
 #
-# Any line of stderr starting with leading blanks and a `+' are filtered
+# Any line of stderr starting with leading blanks and a '+' are filtered
 # out, since most shells when tracing include subshell traces in stderr.
-# This may cause spurious failures when the test suite is run with `-x'.
+# This may cause spurious failures when the test suite is run with '-x'.
 #
 _AT_DEFINE_SETUP([AT_CHECK],
 [_AT_CHECK(m4_expand([$1]), [$2], AS_ESCAPE(m4_dquote(m4_expand([$3]))),
@@ -2091,16 +2091,16 @@ m4_define([AT_CHECK_NOESCAPE],
 # _AT_DECIDE_TRACEABLE(COMMANDS)
 # ------------------------------
 # Worker for _AT_CHECK that expands to shell code.  If COMMANDS are safe to
-# trace with `set -x', the shell code will evaluate to true.  Otherwise,
+# trace with 'set -x', the shell code will evaluate to true.  Otherwise,
 # the shell code will print a message stating an aspect of COMMANDS that makes
 # tracing them unsafe, and evaluate to false.
 #
 # Tracing COMMANDS is not safe if they contain a command that spans multiple
-# lines.  When the test suite user passes `-x' or `--trace', the test suite
-# precedes every command with a `set -x'.  Since most tests expect a specific
+# lines.  When the test suite user passes '-x' or '--trace', the test suite
+# precedes every command with a 'set -x'.  Since most tests expect a specific
 # stderr, if only to confirm that it is empty, the test suite filters ^+ from
 # the captured stderr before comparing with the expected stderr.  If a command
-# spans multiple lines, so will its trace, but a `+' only prefixes the first
+# spans multiple lines, so will its trace, but a '+' only prefixes the first
 # line of that trace:
 #
 # $ echo 'foo
@@ -2143,18 +2143,18 @@ m4_define([AT_CHECK_NOESCAPE],
 #   echo "$var"
 # Parameter expansions appear in COMMANDS with much greater frequency than do
 # newlines and command substitutions, so disabling tracing for all such
-# COMMANDS would much more substantially devalue `testsuite -x'.  To determine
-# which parameter expansions yield multiple lines, we escape all ``', `"',
-# and `\' in a copy of COMMANDS and expand that string within double quotes
+# COMMANDS would much more substantially devalue 'testsuite -x'.  To determine
+# which parameter expansions yield multiple lines, we escape all '`', '"',
+# and '\' in a copy of COMMANDS and expand that string within double quotes
 # at runtime.  If the result of that expansion contains multiple lines, the
 # test suite disables tracing for the command in question.
 #
 # This method leads the test suite to expand some parameters that the shell
 # itself will never expand due to single-quotes or backslash escapes.  This is
-# not a problem for `$foo' expansions, which will simply yield the empty string
-# or some unrelated value.  A `${...}' expansion could actually form invalid
-# shell code, however; consider `${=foo}'.  Therefore, we disable tracing for
-# all COMMANDS containing `${...}'.  This affects few COMMANDS.
+# not a problem for '$foo' expansions, which will simply yield the empty string
+# or some unrelated value.  A '${...}' expansion could actually form invalid
+# shell code, however; consider '${=foo}'.  Therefore, we disable tracing for
+# all COMMANDS containing '${...}'.  This affects few COMMANDS.
 #
 # This macro falls in a very hot path; the Autoconf test suite expands it 1640
 # times as of this writing.  To give a sense of the impact of the heuristics I
@@ -2232,7 +2232,7 @@ m4_define([AT_DIFF_STDOUT()],
 # then the shells will save the traces in at-stderr. So we have to filter
 # them out when checking stderr, and we must send them into the test suite's
 # stderr to honor -x properly. Since only the first line of the trace of a
-# multiline command starts with a `+', and I know of no straightforward way to
+# multiline command starts with a '+', and I know of no straightforward way to
 # filter out the unadorned trace lines, we disable shell tracing entirely for
 # commands that could span multiple lines.
 #
diff --git a/lib/freeze.mk b/lib/freeze.mk
index b7d4bdc1..5462b017 100644
--- a/lib/freeze.mk
+++ b/lib/freeze.mk
@@ -27,16 +27,16 @@ AUTOM4TE_CFG = lib/autom4te.cfg
 
 # Do not use AUTOM4TE here, since maint.mk (my-distcheck)
 # checks if we are independent of Autoconf by defining AUTOM4TE (and
-# others) to `false'.  Autoconf provides autom4te, so that doesn't
+# others) to 'false'.  Autoconf provides autom4te, so that doesn't
 # apply to us.
 MY_AUTOM4TE =                                                                  
\
        autom4te_perllibdir='$(top_srcdir)'/lib                                 
\
        AUTOM4TE_CFG='$(AUTOM4TE_CFG)'         $(top_build_prefix)bin/autom4te  
\
-               -B '$(top_build_prefix)'lib -B '$(top_srcdir)'/lib        # 
keep ` '
+               -B '$(top_build_prefix)'lib -B '$(top_srcdir)'/lib        # 
keep ' '
 
 # When processing the file with diversion disabled, there must be no
 # output but comments and empty lines.
-# If freezing produces output, something went wrong: a bad `divert',
+# If freezing produces output, something went wrong: a bad 'divert',
 # or an improper paren etc.
 # It may happen that the output does not end with an end of line, hence
 # force an end of line when reporting errors.
diff --git a/lib/m4sugar/m4sh.m4 b/lib/m4sugar/m4sh.m4
index ce531520..e0d50431 100644
--- a/lib/m4sugar/m4sh.m4
+++ b/lib/m4sugar/m4sh.m4
@@ -58,7 +58,7 @@
 # Convert a diversion name into its number.  Otherwise, return
 # DIVERSION-NAME which is supposed to be an actual diversion number.
 # Of course it would be nicer to use m4_case here, instead of zillions
-# of little macros, but it then takes twice longer to run `autoconf'!
+# of little macros, but it then takes twice longer to run 'autoconf'!
 m4_define([_m4_divert(BINSH)],             0)
 m4_define([_m4_divert(HEADER-REVISION)],   1)
 m4_define([_m4_divert(HEADER-COMMENT)],    2)
@@ -124,7 +124,7 @@ m4_define([_AS_CLEANUP],
 # ------------------
 # Emit TEXT, a copyright notice, as a shell comment near the top of the
 # script.  TEXT is evaluated once; to accomplish that, we do not prepend
-# `# ' but `@%:@ '.
+# '# ' but '@%:@ '.
 m4_define([AS_COPYRIGHT],
 [m4_divert_text([HEADER-COPYRIGHT],
 [m4_bpatsubst([
@@ -196,7 +196,7 @@ m4_defun([_AS_DETECT_BETTER_SHELL],
 dnl
 dnl By default, do not force re-execution of the script just because
 dnl the user has pre-set $CONFIG_SHELL; do so only if the m4sh client has
-dnl defined the internal variable `_AS_FORCE_REEXEC_WITH_CONFIG_SHELL' to
+dnl defined the internal variable '_AS_FORCE_REEXEC_WITH_CONFIG_SHELL' to
 dnl "yes".
 dnl FIXME: This interface is acceptable for the moment, as a private,
 dnl FIXME: internal one; but if we want to make the "always re-execute"
@@ -276,7 +276,7 @@ _m4_popdef([AS_EXIT])])# _AS_DETECT_BETTER_SHELL
 # _AS_REEXEC_WITH_SHELL(SHELL)
 # ----------------------------
 # Re-execute the current script with the given shell, trying to preserve
-# portable settings (e.g., the `xtrace' and `verbose' shell flag).
+# portable settings (e.g., the 'xtrace' and 'verbose' shell flag).
 m4_defun([_AS_REEXEC_WITH_SHELL], [dnl
 # We cannot yet assume a decent shell, so we have to provide a
 # neutralization value for shells without unset; and this also
@@ -293,7 +293,7 @@ case $- in @%:@ ((((
 esac
 exec $1 $as_opts "$as_myself" ${1+"$[@]"}
 # Admittedly, this is quite paranoid, since all the known shells bail
-# out after a failed `exec'.
+# out after a failed 'exec'.
 AS_ECHO(["$[]0: could not re-execute with $1"]) >&2
 dnl AS_EXIT cannot be used here because as_fn_exit is not yet defined;
 dnl code inserted by AS_REQUIRE_SHELL_FN will appear _after_ this point.
@@ -306,7 +306,7 @@ exit 255])# _AS_REEXEC_WITH_SHELL
 # Ensure that file descriptors 0, 1, and 2 are open, as a defensive
 # measure against weird environments that run configure scripts
 # with these descriptors closed.
-# `exec m>&n` fails in POSIX sh when fd N is closed, but succeeds
+# 'exec m>&n' fails in POSIX sh when fd N is closed, but succeeds
 # regardless of whether fd N is open in some old shells, e.g. Solaris
 # /bin/sh.  This is OK because those shells will be rejected by
 # _AS_DETECT_BETTER_SHELL anyway.
@@ -534,7 +534,7 @@ case $[0] in @%:@((
                   [test -r "$as_dir$[0]" && as_myself=$as_dir$[0] && break])
      ;;
 esac
-# We did not find ourselves, most probably we were run as `sh COMMAND'
+# We did not find ourselves, most probably we were run as 'sh COMMAND'
 # in which case we are not to be found in the path.
 if test "x$as_myself" = x; then
   as_myself=$[0]
@@ -607,7 +607,7 @@ esac])# AS_CASE
 # to set $? prior to the exit.
 # Then there are shells that don't inherit $? correctly into the start of
 # a shell function, so we must always be given an argument.
-# Other shells don't use `$?' as default for `exit', hence just repeating
+# Other shells don't use '$?' as default for 'exit', hence just repeating
 # the exit value can only help improving portability.
 m4_defun([_AS_EXIT_PREPARE],
 [AS_REQUIRE_SHELL_FN([as_fn_set_status],
@@ -675,12 +675,12 @@ done[]_m4_popdef([$1])])
 # Note: IF-TRUEn and IF_FALSE may be nonempty but, after further macro
 # expansion, leave no actual shell code.  We can't detect this, so we
 # include a no-op statement in each clause to prevent it becoming a shell
-# syntax error.  For the IF-TRUEn this can simply be `:' at the beginning of
+# syntax error.  For the IF-TRUEn this can simply be ':' at the beginning of
 # the clause.  IF-FALSE is harder because it must preserve the value of $?
 # from the conditional expression.  The most practical way to do this is
-# with a shell function whose body is `return $?' but AS_IF is used before
+# with a shell function whose body is 'return $?' but AS_IF is used before
 # it's safe to use shell functions.  To deal with *that*, there is a shell
-# variable $as_fn_nop that expands to `:' before the nop shell function is
+# variable $as_fn_nop that expands to ':' before the nop shell function is
 # defined, and invokes the nop shell function afterward.  Early uses of
 # AS_IF (which are all under our control) must not use the value of $? from
 # the conditional expression in an else clause.
@@ -814,8 +814,8 @@ m4_define([_AS_ESCAPE_], [$1])
 #
 # Compatibility glue between the old AS_MSG suite which did not
 # quote anything, and the modern suite which quotes the quotes.
-# If STRING contains `\\' or `\$', it's modern.
-# If STRING contains `\"' or `\`', it's old.
+# If STRING contains '\\' or '\$', it's modern.
+# If STRING contains '\"' or '\`', it's old.
 # Otherwise it's modern.
 #
 # Profiling shows that m4_index is 5 to 8x faster than m4_bregexp.  The
@@ -871,8 +871,8 @@ m4_defun_init([_AS_ECHO_LOG],
 # Don't try to cache, since the results of this macro are needed to
 # display the checking message.  In addition, caching something used once
 # has little interest.
-# Idea borrowed from dist 3.0.  Use `*c*,', not `*c,' because if `\c'
-# failed there is also a newline to match.  Use `xy' because `\c' echoed
+# Idea borrowed from dist 3.0.  Use '*c*,', not '*c,' because if '\c'
+# failed there is also a newline to match.  Use 'xy' because '\c' echoed
 # in a command substitution prints only the first character of the output
 # with ksh version M-11/16/88f on AIX 6.1; it needs to be reset by another
 # backquoted echo.
@@ -897,7 +897,7 @@ esac
 # the shell variables $as_echo and $as_echo_n.  New code should use
 # AS_ECHO(["message"]) and AS_ECHO_N(["message"]), respectively.
 dnl The @&t@ prevents a spurious deprecation diagnostic.
-dnl Extra quoting in case `s' or `n' are user-defined macros when this
+dnl Extra quoting in case 's' or 'n' are user-defined macros when this
 dnl is expanded; they almost certainly aren't meant to be used here.
 dnl See bug 110377.
 as_@&t@echo='printf [%s\n]'
@@ -1033,7 +1033,7 @@ _AS_BASENAME_SED([$1])])
 
 # _AS_BASENAME_PREPARE
 # --------------------
-# Avoid Solaris 9 /usr/ucb/basename, as `basename /' outputs an empty line.
+# Avoid Solaris 9 /usr/ucb/basename, as 'basename /' outputs an empty line.
 # Also, traditional basename mishandles --.  Require here _AS_EXPR_PREPARE,
 # to avoid problems when _AS_BASENAME is called from the M4SH-INIT diversion.
 m4_defun([_AS_BASENAME_PREPARE],
@@ -1109,7 +1109,7 @@ fi
 # (typically a quoted string).  The bytes of WORD are output as-is, even
 # if it starts with "-" or contains "\".
 m4_define([AS_ECHO],
-dnl Extra quoting in case `s' or `n' are user-defined macros when this
+dnl Extra quoting in case 's' or 'n' are user-defined macros when this
 dnl is expanded; they almost certainly aren't meant to be used here.
 dnl See bug 110377.
 [printf "[%s\n]" $1])
@@ -1124,7 +1124,7 @@ m4_define([as_echo],
 # ---------------
 # Like AS_ECHO(WORD), except do not output the trailing newline.
 m4_define([AS_ECHO_N],
-dnl Extra quoting in case `s' is a user-defined macro when this
+dnl Extra quoting in case 's' is a user-defined macro when this
 dnl is expanded; it almost certainly isn't meant to be used here.
 dnl See bug 110377.
 [printf [%s] $1])
@@ -1269,7 +1269,7 @@ _m4_popdef([AS_MESSAGE_LOG_FD], [AS_ERROR])])# 
_AS_LINENO_PREPARE
 # _AS_LN_S_PREPARE
 # ----------------
 # Don't use conftest.sym to avoid file name issues on DJGPP, where this
-# would yield conftest.sym.exe for DJGPP < 2.04.  And don't use `conftest'
+# would yield conftest.sym.exe for DJGPP < 2.04.  And don't use 'conftest'
 # as base name to avoid prohibiting concurrency (e.g., concurrent
 # config.statuses).  On read-only media, assume 'cp -pR' and hope we
 # are just running --help anyway.
@@ -1285,9 +1285,9 @@ if (echo >conf$$.file) 2>/dev/null; then
   if ln -s conf$$.file conf$$ 2>/dev/null; then
     as_ln_s='ln -s'
     # ... but there are two gotchas:
-    # 1) On MSYS, both `ln -s file dir' and `ln file dir' fail.
-    # 2) DJGPP < 2.04 has no symlinks; `ln -s' creates a wrapper executable.
-    # In both cases, we have to default to `cp -pR'.
+    # 1) On MSYS, both 'ln -s file dir' and 'ln file dir' fail.
+    # 2) DJGPP < 2.04 has no symlinks; 'ln -s' creates a wrapper executable.
+    # In both cases, we have to default to 'cp -pR'.
     ln -s conf$$.file conf$$.dir 2>/dev/null && test ! -f conf$$.exe ||
       as_ln_s='cp -pR'
   elif ln conf$$.file conf$$ 2>/dev/null; then
@@ -1306,7 +1306,7 @@ rmdir conf$$.dir 2>/dev/null
 # AS_LN_S(FILE, LINK)
 # -------------------
 # FIXME: Should we add the glue code to handle properly relative symlinks
-# simulated with `ln' or `cp'?
+# simulated with 'ln' or 'cp'?
 m4_defun_init([AS_LN_S],
 [AS_REQUIRE([_AS_LN_S_PREPARE])],
 [$as_ln_s $1 $2])
@@ -1314,7 +1314,7 @@ m4_defun_init([AS_LN_S],
 
 # _AS_MKDIR_P
 # -----------
-# Emit code that can be used to emulate `mkdir -p` with plain `mkdir';
+# Emit code that can be used to emulate 'mkdir -p' with plain 'mkdir';
 # the code assumes that "$as_dir" contains the directory to create.
 # $as_dir is normalized, so there is no need to worry about using --.
 m4_define([_AS_MKDIR_P],
@@ -1338,7 +1338,7 @@ m4_define([_AS_MKDIR_P],
 
 # AS_MKDIR_P(DIR)
 # ---------------
-# Emulate `mkdir -p' with plain `mkdir' if needed.
+# Emulate 'mkdir -p' with plain 'mkdir' if needed.
 m4_defun_init([AS_MKDIR_P],
 [AS_REQUIRE([_$0_PREPARE])],
 [as_dir=$1; as_fn_mkdir_p])# AS_MKDIR_P
@@ -1379,12 +1379,12 @@ fi
 
 # _AS_PATH_WALK([PATH = $PATH], BODY, [IF-NOT-FOUND])
 # ---------------------------------------------------
-# Walk through PATH running BODY for each `as_dir', with a trailing slash
-# already present.  If BODY never does a `break', evaluate IF-NOT-FOUND.
+# Walk through PATH running BODY for each 'as_dir', with a trailing slash
+# already present.  If BODY never does a 'break', evaluate IF-NOT-FOUND.
 #
 # Still very private as its interface looks quite bad.
 #
-# `$as_dummy' forces splitting on constant user-supplied paths.
+# '$as_dummy' forces splitting on constant user-supplied paths.
 # POSIX.2 field splitting is done only on the result of word
 # expansions, not on literal text.  This closes a longstanding sh security
 # hole.  Optimize it away when not needed, i.e., if there are no literal
@@ -1431,7 +1431,7 @@ esac[]])# AS_SET_CATFILE
 
 # _AS_TEST_X_WORKS
 # ----------------
-# These days, we require that `test -x' works.
+# These days, we require that 'test -x' works.
 m4_define([_AS_TEST_X_WORKS], [test -x /])
 
 # _AS_TEST_PREPARE
@@ -1457,10 +1457,10 @@ as_executable_p=as_fn_executable_p
 # This section is lexicographically sorted.
 
 
-# AS_BOX(MESSAGE, [FRAME-CHARACTER = `-'])
+# AS_BOX(MESSAGE, [FRAME-CHARACTER = '-'])
 # ----------------------------------------
 # Output MESSAGE, a single line text, framed with FRAME-CHARACTER (which
-# must not be `/').
+# must not be '/').
 m4_define([AS_BOX],
 [_$0(m4_expand([$1]), [$2])])
 
@@ -1469,13 +1469,13 @@ m4_define([_AS_BOX],
   [-1], [$0_LITERAL], [$0_INDIR])($@)])
 
 
-# _AS_BOX_LITERAL(MESSAGE, [FRAME-CHARACTER = `-'])
+# _AS_BOX_LITERAL(MESSAGE, [FRAME-CHARACTER = '-'])
 # -------------------------------------------------
 m4_define([_AS_BOX_LITERAL],
 [AS_ECHO(["_AS_ESCAPE(m4_dquote(m4_expand([m4_text_box($@)])), [`], [\"$])"])])
 
 
-# _AS_BOX_INDIR(MESSAGE, [FRAME-CHARACTER = `-'])
+# _AS_BOX_INDIR(MESSAGE, [FRAME-CHARACTER = '-'])
 # -----------------------------------------------
 m4_define([_AS_BOX_INDIR],
 [sed 'h;s/./m4_default([$2], [-])/g;s/^.../@%:@@%:@ /;s/...$/ 
@%:@@%:@/;p;x;p;x' <<_ASBOX
@@ -1577,7 +1577,7 @@ m4_define([AS_HELP_STRING],
 # AS_IDENTIFIER_IF(EXPRESSION, IF-IDENT, IF-NOT-IDENT)
 # ----------------------------------------------------
 # If EXPRESSION serves as an identifier (ie, after removal of @&t@, it
-# matches the regex `^[a-zA-Z_][a-zA-Z_0-9]*$'), execute IF-IDENT,
+# matches the regex '^[a-zA-Z_][a-zA-Z_0-9]*$'), execute IF-IDENT,
 # otherwise IF-NOT-IDENT.
 #
 # This is generally faster than the alternative:
@@ -1615,19 +1615,19 @@ m4_dquote(m4_dquote(m4_defn([m4_cr_symbols1])))[[))], 
[0], [-])])
 # EXPRESSION is treated as a literal if it results in the same
 # interpretation whether it is unquoted or contained within double
 # quotes, with the exception that whitespace is ignored (on the
-# assumption that it will be flattened to _).  Therefore, neither `\$'
-# nor `a''b' is a literal, since both backslash and single quotes have
-# different quoting behavior in the two contexts; and `a*' is not a
+# assumption that it will be flattened to _).  Therefore, neither '\$'
+# nor 'a''b' is a literal, since both backslash and single quotes have
+# different quoting behavior in the two contexts; and 'a*' is not a
 # literal, because it has different globbing.  Note, however, that
-# while `${a+b}' is neither a literal nor a simple ref, `a+b' is a
+# while '${a+b}' is neither a literal nor a simple ref, 'a+b' is a
 # literal.  This macro is an *approximation*: it is possible that
 # there are some EXPRESSIONs which the shell would treat as literals,
 # but which this macro does not recognize.
 #
-# Why do we reject EXPRESSION expanding with `[' or `]' as a literal?
+# Why do we reject EXPRESSION expanding with '[' or ']' as a literal?
 # Because AS_TR_SH is MUCH faster if it can use m4_translit on literals
 # instead of m4_bpatsubst; but m4_translit is much tougher to do safely
-# if `[' is translated.  That, and file globbing matters.
+# if '[' is translated.  That, and file globbing matters.
 #
 # Note that the quadrigraph @S|@ can result in non-literals, but outright
 # rejecting all @ would make AC_INIT complain on its bug report address.
@@ -1638,11 +1638,11 @@ m4_dquote(m4_dquote(m4_defn([m4_cr_symbols1])))[[))], 
[0], [-])])
 # Because the translit is stripping quotes, it must also neutralize
 # anything that might be in a macro name, as well as comments, commas,
 # or unbalanced parentheses.  Valid shell variable characters and
-# unambiguous literal characters are deleted (`a.b'), and remaining
-# characters are normalized into `$' if they can form simple refs
-# (${a}), `+' if they can potentially form literals (a+b), ``' if they
-# can interfere with m4 parsing, or left alone otherwise.  If both `$'
-# and `+' are left, it is treated as a complex reference (${a+b}),
+# unambiguous literal characters are deleted ('a.b'), and remaining
+# characters are normalized into '$' if they can form simple refs
+# (${a}), '+' if they can potentially form literals (a+b), '`' if they
+# can interfere with m4 parsing, or left alone otherwise.  If both '$'
+# and '+' are left, it is treated as a complex reference (${a+b}),
 # even though it could technically be a simple reference (${a}+b).
 # _AS_LITERAL_IF_ only has to check for an empty string after removing
 # one of the two normalized characters.
@@ -1839,7 +1839,7 @@ AS_CASE([$?],
 ## --------------------------------------- ##
 
 # The point of this section is to provide high level macros comparable
-# to m4's `translit' primitive, but m4/sh polymorphic.
+# to m4's 'translit' primitive, but m4/sh polymorphic.
 # Transliteration of literal strings should be handled by m4, while
 # shell variables' content will be translated at runtime (tr or sed).
 
@@ -1871,7 +1871,7 @@ as_tr_sh="eval sed 'y%*+%pp%;s%[[^_$as_cr_alnum]]%_%g'"
 # --------------------
 # Transform EXPRESSION into a valid shell variable name.
 # sh/m4 polymorphic.
-# Be sure to update the definition of `$as_tr_sh' if you change this.
+# Be sure to update the definition of '$as_tr_sh' if you change this.
 #
 # AS_LITERAL_IF guarantees that a literal does not have any nested quotes,
 # once $1 is expanded.  m4_translit silently uses only the first occurrence
@@ -1910,8 +1910,8 @@ as_tr_cpp="eval sed 
'y%*$as_cr_letters%P$as_cr_LETTERS%;s%[[^_$as_cr_alnum]]%_%g
 # AS_TR_CPP(EXPRESSION)
 # ---------------------
 # Map EXPRESSION to an upper case string which is valid as rhs for a
-# `#define'.  sh/m4 polymorphic.  Be sure to update the definition
-# of `$as_tr_cpp' if you change this.
+# '#define'.  sh/m4 polymorphic.  Be sure to update the definition
+# of '$as_tr_cpp' if you change this.
 #
 # See implementation comments in AS_TR_SH.
 m4_defun_init([AS_TR_CPP],
@@ -2054,7 +2054,7 @@ m4_define([AS_VAR_COPY],
 # --------------------
 # Get the value of the shell VARIABLE.
 # Evaluates to $VARIABLE if there is no indirection in VARIABLE,
-# else to the appropriate `eval' sequence.
+# else to the appropriate 'eval' sequence.
 # This macro is deprecated because it sometimes mishandles trailing newlines;
 # use AS_VAR_COPY instead.
 m4_define([AS_VAR_GET],
@@ -2065,7 +2065,7 @@ m4_define([AS_VAR_GET],
 
 # AS_VAR_IF(VARIABLE, VALUE, IF-TRUE, IF-FALSE)
 # ---------------------------------------------
-# Implement a shell `if test $VARIABLE = VALUE; then-else'.
+# Implement a shell 'if test $VARIABLE = VALUE; then-else'.
 # Polymorphic, and avoids sh expansion error upon interrupt or term signal.
 m4_define([AS_VAR_IF],
 [AS_LITERAL_WORD_IF([$1],
@@ -2082,20 +2082,20 @@ m4_define([AS_VAR_IF],
 # --------------------------------
 #
 
-# Sometimes we may have to handle literals (e.g. `stdlib.h'), while at
+# Sometimes we may have to handle literals (e.g. 'stdlib.h'), while at
 # other moments, the same code may have to get the value from a
-# variable (e.g., `ac_header').  To have a uniform handling of both
+# variable (e.g., 'ac_header').  To have a uniform handling of both
 # cases, when a new value is about to be processed, declare a local
 # variable, e.g.:
 #
 #   AS_VAR_PUSHDEF([header], [ac_cv_header_$1])
 #
-# and then in the body of the macro, use `header' as is.  It is of
-# first importance to use `AS_VAR_*' to access this variable.
+# and then in the body of the macro, use 'header' as is.  It is of
+# first importance to use 'AS_VAR_*' to access this variable.
 #
-# If the value `$1' was a literal (e.g. `stdlib.h'), then `header' is
-# in fact the value `ac_cv_header_stdlib_h'.  If `$1' was indirect,
-# then `header's value in m4 is in fact `$as_header', the shell
+# If the value '$1' was a literal (e.g. 'stdlib.h'), then 'header' is
+# in fact the value 'ac_cv_header_stdlib_h'.  If '$1' was indirect,
+# then the value of 'header' in m4 is in fact '$as_header', the shell
 # variable that holds all of the magic to get the expansion right.
 #
 # At the end of the block, free the variable with
@@ -2145,7 +2145,7 @@ m4_define([AS_VAR_SET],
 
 # AS_VAR_SET_IF(VARIABLE, IF-TRUE, IF-FALSE)
 # ------------------------------------------
-# Implement a shell `if-then-else' depending whether VARIABLE is set
+# Implement a shell 'if-then-else' depending whether VARIABLE is set
 # or not.  Polymorphic.
 m4_define([AS_VAR_SET_IF],
 [AS_IF([AS_VAR_TEST_SET([$1])], [$2], [$3])])
@@ -2172,7 +2172,7 @@ m4_define([AS_VAR_TEST_SET],
 # Generate a child script FILE with all initialization necessary to
 # reuse the environment learned by the parent script, and make the
 # file executable.  If COMMENT is supplied, it is inserted after the
-# `#!' sequence but before initialization text begins.  After this
+# '#!' sequence but before initialization text begins.  After this
 # macro, additional text can be appended to FILE to form the body of
 # the child script.  The macro ends with non-zero status if the
 # file could not be fully written (such as if the disk is full).
diff --git a/lib/m4sugar/m4sugar.m4 b/lib/m4sugar/m4sugar.m4
index 0ea671d7..ebb3dc25 100644
--- a/lib/m4sugar/m4sugar.m4
+++ b/lib/m4sugar/m4sugar.m4
@@ -64,9 +64,9 @@ m4_undefine([undefine])
 # 2. m4_define([to], [from($@)])
 # Well, obviously 1 is more expensive in space.  Maybe 2 is more expensive
 # in time, but because of the space cost of 1, it's not that obvious.
-# Nevertheless, one huge difference is the handling of `$0'.  If `from'
-# uses `$0', then with 1, `to''s `$0' is `to', while it is `from' in 2.
-# The user would certainly prefer to see `to'.
+# Nevertheless, one huge difference is the handling of '$0'.  If 'from'
+# uses '$0', then with 1, 'to''s '$0' is 'to', while it is 'from' in 2.
+# The user would certainly prefer to see 'to'.
 #
 # This definition is in effect during m4sugar initialization, when
 # there are no pushdef stacks; later on, we redefine it to something
@@ -97,7 +97,7 @@ m4_define([m4_copy_unm4],
 
 
 # Some m4 internals have names colliding with tokens we might use.
-# Rename them a` la `m4 --prefix-builtins'.  Conditionals first, since
+# Rename them à la 'm4 --prefix-builtins'.  Conditionals first, since
 # some subsequent renames are conditional.
 m4_rename_m4([ifdef])
 m4_rename([ifelse], [m4_if])
@@ -194,7 +194,7 @@ m4_define([m4_location],
 
 # m4_errprintn(MSG)
 # -----------------
-# Same as `errprint', but with the missing end of line.
+# Same as 'errprint', but with the missing end of line.
 m4_define([m4_errprintn],
 [m4_errprint([$1
 ])])
@@ -273,7 +273,7 @@ m4_ifdef([_m4_expansion_stack], [m4_expansion_stack]))])
 # been included.
 m4_define([m4_include_unique],
 [m4_ifdef([m4_include($1)],
-         [m4_warn([syntax], [file `$1' included several times])])dnl
+         [m4_warn([syntax], [file '$1' included several times])])dnl
 m4_define([m4_include($1)])])
 
 
@@ -298,16 +298,16 @@ m4_builtin([sinclude], [$1])])
 ## 5. Additional branching constructs.  ##
 ## ------------------------------------ ##
 
-# Both `m4_ifval' and `m4_ifset' tests against the empty string.  The
-# difference is that `m4_ifset' is specialized on macros.
+# Both 'm4_ifval' and 'm4_ifset' tests against the empty string.  The
+# difference is that 'm4_ifset' is specialized on macros.
 #
 # In case of arguments of macros, eg. $1, it makes little difference.
-# In the case of a macro `FOO', you don't want to check `m4_ifval(FOO,
-# TRUE)', because if `FOO' expands with commas, there is a shifting of
-# the arguments.  So you want to run `m4_ifval([FOO])', but then you just
-# compare the *string* `FOO' against `', which, of course fails.
+# In the case of a macro 'FOO', you don't want to check 'm4_ifval(FOO,
+# TRUE)', because if 'FOO' expands with commas, there is a shifting of
+# the arguments.  So you want to run 'm4_ifval([FOO])', but then you just
+# compare the *string* 'FOO' against '', which, of course fails.
 #
-# So you want the variation `m4_ifset' that expects a macro name as $1.
+# So you want the variation 'm4_ifset' that expects a macro name as $1.
 # If this macro is both defined and defined to a non empty value, then
 # it runs TRUE, etc.
 
@@ -355,7 +355,7 @@ m4_define([m4_n],
 
 # m4_ifvaln(COND, [IF-TRUE], [IF-FALSE])
 # --------------------------------------
-# Same as `m4_ifval', but add an extra newline to IF-TRUE or IF-FALSE
+# Same as 'm4_ifval', but add an extra newline to IF-TRUE or IF-FALSE
 # unless that argument is empty.
 m4_define([m4_ifvaln],
 [m4_if([$1],
@@ -530,7 +530,7 @@ m4_define([_m4_cond],
 # All the values are optional, and the macro is robust to active symbols
 # properly quoted.
 #
-# I would have liked to name this macro `m4_bpatsubst', unfortunately,
+# I would have liked to name this macro 'm4_bpatsubst', unfortunately,
 # due to quotation problems, I need to double quote $1 below, therefore
 # the anchors are broken :(  I can't let users be trapped by that.
 #
@@ -675,7 +675,7 @@ m4_define([_m4_dumpdef],
 
 # m4_dumpdefs(NAME...)
 # --------------------
-# Similar to `m4_dumpdef(NAME)', but if NAME was m4_pushdef'ed, display its
+# Similar to 'm4_dumpdef(NAME)', but if NAME was m4_pushdef'ed, display its
 # value stack (most recent displayed first).  Also, this version silently
 # ignores undefined macros, rather than erroring out.
 #
@@ -723,7 +723,7 @@ m4_define([m4_popdef],
 # result is strictly equivalent to
 #   m4_if([$1], 1, [m4_shift(,m4_shift(m4_shift($@)))],
 #         [_m4_shiftn(m4_decr([$1]), m4_shift(m4_shift($@)))])
-# but with the final `m4_shift(m4_shift($@)))' shared between the two
+# but with the final 'm4_shift(m4_shift($@)))' shared between the two
 # paths.  The first leg uses a no-op m4_shift(,$@) to balance out the ().
 #
 # Please keep foreach.m4 in sync with any adjustments made here.
@@ -893,8 +893,8 @@ m4_define([m4_echo], [$@])
 # Unfortunately, due to limitations in m4, ARG must expand to
 # something with balanced quotes (use quadrigraphs to get around
 # this), and should not contain the unlikely delimiters -=<{( or
-# )}>=-.  It is possible to have unbalanced quoted `(' or `)', as well
-# as unbalanced unquoted `)'.  m4_expand can handle unterminated
+# )}>=-.  It is possible to have unbalanced quoted '(' or ')', as well
+# as unbalanced unquoted ')'.  m4_expand can handle unterminated
 # comments or dnl on the final line, at the expense of speed; it also
 # aids in detecting attempts to incorrectly change the current
 # diversion inside ARG.  Meanwhile, _m4_expand is faster but must be
@@ -908,10 +908,10 @@ m4_define([m4_echo], [$@])
 # the unquoted () that were added prior to the changequote.
 #
 # Thanks to shell case statements, too many people are prone to pass
-# underquoted `)', so we try to detect that by passing a marker as a
+# underquoted ')', so we try to detect that by passing a marker as a
 # fourth argument; if the marker is not present, then we assume that
-# we encountered an early `)', and re-expand the first argument, but
-# this time with one more `(' in the second argument and in the
+# we encountered an early ')', and re-expand the first argument, but
+# this time with one more '(' in the second argument and in the
 # open-quote delimiter.  We must also ignore the slop from the
 # previous try.  The final macro is thus half line-noise, half art.
 m4_define([m4_expand],
@@ -965,10 +965,10 @@ m4_define([m4_noquote],
 # Return ARGS as a single argument.  Any whitespace after unquoted commas
 # is stripped.  There is always output, even when there were no arguments.
 #
-# It is important to realize the difference between `m4_quote(exp)' and
-# `[exp]': in the first case you obtain the quoted *result* of the
+# It is important to realize the difference between 'm4_quote(exp)' and
+# '[exp]': in the first case you obtain the quoted *result* of the
 # expansion of EXP, while in the latter you just obtain the string
-# `exp'.
+# 'exp'.
 m4_define([m4_quote],  [[$*]])
 
 
@@ -1042,7 +1042,7 @@ m4_define([_m4_for],
                 [$0(m4_eval([$1 + $3]), [$2], [$3], [$4], [$5])])])
 
 
-# Implementing `foreach' loops in m4 is much more tricky than it may
+# Implementing 'foreach' loops in m4 is much more tricky than it may
 # seem.  For example, the old M4 1.4.4 manual had an incorrect example,
 # which looked like this (when translated to m4sugar):
 #
@@ -1106,7 +1106,7 @@ m4_define([_m4_for],
 # |    [m4_define([$1], [_arg1($2)])$3[]_foreach([$1], [m4_shift($2)], 
[$3])])])
 #
 #
-# Now, just replace the `$2' with `m4_quote($2)' in the outer `m4_if'
+# Now, just replace the '$2' with 'm4_quote($2)' in the outer 'm4_if'
 # to improve robustness, and you come up with a nice implementation
 # that doesn't require extra parentheses in the user's LIST.
 #
@@ -1128,7 +1128,7 @@ m4_define([_m4_for],
 # --------------------------------------
 #
 # Expand EXPRESSION assigning each value of the LIST to VARIABLE.
-# LIST should have the form `item_1, item_2, ..., item_n', i.e. the
+# LIST should have the form 'item_1, item_2, ..., item_n', i.e. the
 # whole list must *quoted*.  Quote members too if you don't want them
 # to be expanded.
 #
@@ -1472,7 +1472,7 @@ m4_define([m4_divert_once],
 # DIVERSION-NAME is unsafe, because this macro is being expanded
 # during argument collection of m4_expand.
 m4_define([_m4_divert_unsafe],
-[m4_fatal([$0: cannot change diversion to `$1' inside m4_expand])])
+[m4_fatal([$0: cannot change diversion to '$1' inside m4_expand])])
 
 
 # m4_undivert(DIVERSION-NAME...)
@@ -1490,8 +1490,8 @@ m4_define([m4_undivert],
 ## 10. Defining macros with bells and whistles.  ##
 ## --------------------------------------------- ##
 
-# `m4_defun' is basically `m4_define' but it equips the macro with the
-# needed machinery for `m4_require'.  A macro must be m4_defun'd if
+# 'm4_defun' is basically 'm4_define' but it equips the macro with the
+# needed machinery for 'm4_require'.  A macro must be m4_defun'd if
 # either it is m4_require'd, or it m4_require's.
 #
 # Two things deserve attention and are detailed below:
@@ -1671,7 +1671,7 @@ m4_define([m4_undivert],
 #
 # We have not tried to simulate the old behavior (better yet, we
 # diagnose it), because it is too dangerous: a macro m4_require'd from
-# the top level is expanded before the body of `configure', i.e., before
+# the top level is expanded before the body of 'configure', i.e., before
 # any other test was run.  I let you imagine the result of requiring
 # AC_STDC_HEADERS for instance, before AC_PROG_CC was actually run....
 #
@@ -1763,7 +1763,7 @@ m4_define([m4_undivert],
 # which must be collected in a new diversion.  While expanding TEST2,
 # we encounter a requirement for TEST1, but since it has already been
 # expanded, the Axel Thimm algorithm states that we can treat it as a
-# no-op.  But that would lead to an end result of `2 3 1', meaning
+# no-op.  But that would lead to an end result of '2 3 1', meaning
 # that we have once again output a macro (TEST2) prior to its
 # requirements (TEST1).
 #
@@ -1809,7 +1809,7 @@ m4_define([m4_undivert],
 # set is checked.  If a macro is in the set, then it has been provided
 # before it was required, and we satisfy dependencies by expanding the
 # macro as if it had never been provided; in the example given above,
-# this means we now output `1 2 3 1'.  Meanwhile, a warning is issued
+# this means we now output '1 2 3 1'.  Meanwhile, a warning is issued
 # to inform the user that her macros trigger the bug in older autoconf
 # versions, and that her output file now contains redundant contents
 # (and possibly new problems, if the repeated macro was not
@@ -1822,7 +1822,7 @@ m4_define([m4_undivert],
 #
 # When M4 expansion goes wrong it is often extremely hard to find the
 # path amongst macros that drove to the failure.  What is needed is
-# the stack of macro `calls'. One could imagine that GNU M4 would
+# the stack of macro 'calls'. One could imagine that GNU M4 would
 # maintain a stack of macro expansions, unfortunately it doesn't, so
 # we do it by hand.  This is of course extremely costly, but the help
 # this stack provides is worth it.  Nevertheless to limit the
@@ -2046,18 +2046,18 @@ m4_define([m4_before],
 # - BODY-TO-EXPAND == m4_indir([NAME-TO-CHECK])
 #   In the case of macros with irregular names.  For instance:
 #     m4_require([AC_LANG_COMPILER(C)], [indir([AC_LANG_COMPILER(C)])])
-#   which means `if the macro named `AC_LANG_COMPILER(C)' (the parens are
+#   which means 'if the macro named 'AC_LANG_COMPILER(C)' (the parens are
 #   part of the name, it is not an argument) has not been run, then
 #   call it.'
 #   Had you used
 #     m4_require([AC_LANG_COMPILER(C)], [AC_LANG_COMPILER(C)])
-#   then m4_require would have tried to expand `AC_LANG_COMPILER(C)', i.e.,
-#   call the macro `AC_LANG_COMPILER' with `C' as argument.
+#   then m4_require would have tried to expand 'AC_LANG_COMPILER(C)', i.e.,
+#   call the macro 'AC_LANG_COMPILER' with 'C' as argument.
 #
-#   You could argue that `AC_LANG_COMPILER', when it receives an argument
-#   such as `C' should dispatch the call to `AC_LANG_COMPILER(C)'.  But this
-#   `extension' prevents `AC_LANG_COMPILER' from having actual arguments that
-#   it passes to `AC_LANG_COMPILER(C)'.
+#   You could argue that 'AC_LANG_COMPILER', when it receives an argument
+#   such as 'C' should dispatch the call to 'AC_LANG_COMPILER(C)'.  But this
+#   'extension' prevents 'AC_LANG_COMPILER' from having actual arguments that
+#   it passes to 'AC_LANG_COMPILER(C)'.
 #
 # This is called frequently, so minimize the number of macro invocations
 # by avoiding dnl and other overhead on the common path.
@@ -2106,7 +2106,7 @@ m4_provide_if([$1], [m4_set_remove([_m4_provide], [$1])],
 m4_define([_m4_require_check],
 [m4_if(_m4_defn([_m4_diverting]), [$2], [m4_ignore],
        m4_ifdef([_m4_diverting([$2])], [-]), [-], [m4_warn([syntax],
-   [$3: `$1' was expanded before it was required
+   [$3: '$1' was expanded before it was required
 
https://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required])_m4_require_call],
        [m4_ignore])])
 
@@ -2190,7 +2190,7 @@ m4_defn([m4_cr_digits])dnl
 
 # m4_cr_all
 # ---------
-# The character range representing everything, with `-' as the last
+# The character range representing everything, with '-' as the last
 # character, since it is special to m4_translit.  Use with care, because
 # it contains characters special to M4 (fortunately, both ASCII and EBCDIC
 # have [] in order, so m4_defn([m4_cr_all]) remains a valid string).  It
@@ -2204,7 +2204,7 @@ m4_defn([m4_cr_digits])dnl
 #
 # It is mainly useful in generating inverted character range maps, for use
 # in places where m4_translit is faster than an equivalent m4_bpatsubst;
-# the regex `[^a-z]' is equivalent to:
+# the regex '[^a-z]' is equivalent to:
 #  m4_translit(m4_dquote(m4_defn([m4_cr_all])), [a-z])
 m4_define([m4_cr_all],
 m4_translit(m4_dquote(m4_format(m4_dquote(m4_for(
@@ -2256,7 +2256,7 @@ m4_define([m4_re_escape],
 
 # m4_re_string
 # ------------
-# Regexp for `[a-zA-Z_0-9]*'
+# Regexp for '[a-zA-Z_0-9]*'
 # m4_dquote provides literal [] for the character class.
 m4_define([m4_re_string],
 m4_dquote(m4_defn([m4_cr_symbols2]))dnl
@@ -2266,7 +2266,7 @@ m4_dquote(m4_defn([m4_cr_symbols2]))dnl
 
 # m4_re_word
 # ----------
-# Regexp for `[a-zA-Z_][a-zA-Z_0-9]*'
+# Regexp for '[a-zA-Z_][a-zA-Z_0-9]*'
 m4_define([m4_re_word],
 m4_dquote(m4_defn([m4_cr_symbols1]))dnl
 m4_defn([m4_re_string])dnl
@@ -2311,7 +2311,7 @@ m4_define([m4_toupper],
 #   m4_split([active active ])end
 #   => [active], [active], []end
 #
-# Optimize on regex of ` ' (space), since m4_foreach_w already guarantees
+# Optimize on regex of ' ' (space), since m4_foreach_w already guarantees
 # that the list contains single space separators, and a common case is
 # splitting a single-element list.  This macro is called frequently,
 # so avoid unnecessary dnl inside the definition.
@@ -2381,12 +2381,12 @@ m4_define([m4_flatten],
 #    => active activeend
 #
 # First, notice that we guarantee trailing space.  Why?  Because regular
-# expressions are greedy, and `.* ?' would always group the space into the
-# .* portion.  The algorithm is simpler by avoiding `?' at the end.  The
-# algorithm correctly strips everything if STRING is just ` '.
+# expressions are greedy, and '.* ?' would always group the space into the
+# .* portion.  The algorithm is simpler by avoiding '?' at the end.  The
+# algorithm correctly strips everything if STRING is just ' '.
 #
 # Then notice the second pattern: it is in charge of removing the
-# leading/trailing spaces.  Why not just `[^ ]'?  Because they are
+# leading/trailing spaces.  Why not just '[^ ]'?  Because they are
 # applied to over-quoted strings, i.e. more or less [STRING], due
 # to the limitations of m4_bpatsubsts.  So the leading space in STRING
 # is the *second* character; equally for the trailing space.
@@ -2420,7 +2420,7 @@ m4_define([m4_normalize],
 # This is used in several Autoconf macros that take a
 # whitespace-separated list of symbols as an argument.  Ideally that
 # list would not be expanded before use, but several packages used
-# `dnl' to put comments inside those lists, so they must be expanded
+# 'dnl' to put comments inside those lists, so they must be expanded
 # for compatibility's sake.
 m4_define([m4_validate_w],
 [_m4_validate_w(m4_normalize([$1]), m4_normalize(m4_expand([$1])))])
@@ -2430,7 +2430,7 @@ m4_define([_m4_validate_w],
   [m4_warn([obsolete], [whitespace-separated list contains macros;
 in a future version of Autoconf they will not be expanded]dnl
 m4_if(m4_bregexp([$1], [\bdn[l]\b]), -1, [], [
-note: `dn@&t@l' is a macro]))])dnl
+note: 'dn@&t@l' is a macro]))])dnl
 [$2]])
 
 
@@ -2446,7 +2446,7 @@ note: `dn@&t@l' is a macro]))])dnl
 # and outputs just that element; while _m4_join looks for all non-empty
 # elements, and outputs them following a separator.  The final trick to
 # note is that we decide between recursing with $0 or _$0 based on the
-# nested m4_if ending with `_'.
+# nested m4_if ending with '_'.
 #
 # Please keep foreach.m4 in sync with any adjustments made here.
 m4_define([m4_join],
@@ -2490,10 +2490,10 @@ m4_define([m4_combine],
 
 # m4_append(MACRO-NAME, STRING, [SEPARATOR])
 # ------------------------------------------
-# Redefine MACRO-NAME to hold its former content plus `SEPARATOR`'STRING'
+# Redefine MACRO-NAME to hold its former content plus 'SEPARATOR''STRING'
 # at the end.  It is valid to use this macro with MACRO-NAME undefined,
 # in which case no SEPARATOR is added.  Be aware that the criterion is
-# `not being defined', and not `not being empty'.
+# 'not being defined', and not 'not being empty'.
 #
 # Note that neither STRING nor SEPARATOR are expanded here; rather, when
 # you expand MACRO-NAME, they will be expanded at that point in time.
@@ -2549,7 +2549,7 @@ m4_define([m4_append],
 
 # m4_append_uniq(MACRO-NAME, STRING, [SEPARATOR], [IF-UNIQ], [IF-DUP])
 # --------------------------------------------------------------------
-# Like `m4_append', but append only if not yet present.  Additionally,
+# Like 'm4_append', but append only if not yet present.  Additionally,
 # expand IF-UNIQ if STRING was appended, or IF-DUP if STRING was already
 # present.  Also, warn if SEPARATOR is not empty and occurs within STRING,
 # as the algorithm no longer guarantees uniqueness.
@@ -2560,7 +2560,7 @@ m4_define([m4_append],
 m4_define([m4_append_uniq],
 [m4_ifval([$3], [m4_if(m4_index([$2], [$3]), [-1], [],
                       [m4_warn([syntax],
-                               [$0: `$2' contains `$3'])])])_$0($@)])
+                               [$0: '$2' contains '$3'])])])_$0($@)])
 m4_define([_m4_append_uniq],
 [m4_ifdef([$1],
          [m4_if(m4_index([$3]_m4_defn([$1])[$3], [$3$2$3]), [-1],
@@ -2648,7 +2648,7 @@ m4_define([_m4_escape],
 # This macro does not leave a trailing space behind the last word of a line,
 # which complicates it a bit.  The algorithm is otherwise stupid and simple:
 # all the words are preceded by m4_Separator which is defined to empty for
-# the first word, and then ` ' (single space) for all the others.
+# the first word, and then ' ' (single space) for all the others.
 #
 # The algorithm uses a helper that uses $2 through $4 directly, rather than
 # using local variables, to avoid m4_defn overhead, or expansion swallowing
@@ -2690,7 +2690,7 @@ m4_define([_m4_text_wrap_word],
 [$2]],
       [m4_Separator[]])[$1]])
 
-# m4_text_box(MESSAGE, [FRAME-CHARACTER = `-'])
+# m4_text_box(MESSAGE, [FRAME-CHARACTER = '-'])
 # ---------------------------------------------
 # Turn MESSAGE into:
 #  ## ------- ##
@@ -2722,7 +2722,7 @@ m4_define([m4_text_box],
 #
 # Avoid bpatsubsts for the common case of no quadrigraphs.  Cache
 # results, as configure scripts tend to ask about lengths of common
-# strings like `/*' and `*/' rather frequently.  Minimize the number
+# strings like '/*' and '*/' rather frequently.  Minimize the number
 # of times that $1 occurs in m4_qlen, so there is less text to parse
 # on a cache hit.
 m4_define([m4_qlen],
@@ -2866,7 +2866,7 @@ m4_define([m4_sign],
 #
 # This macro expects reasonable version numbers, but can handle double
 # letters and does not expand any macros.  Original version strings can
-# use both `.' and `-' separators.
+# use both '.' and '-' separators.
 #
 # Inline constant expansions, to avoid m4_defn overhead.
 # _m4_version_unletter is the real workhorse used by m4_version_compare,
@@ -3290,7 +3290,7 @@ m4_divert_push([KILL])
 # -------
 # Initialize the m4sugar language.
 m4_define([m4_init],
-[# All the M4sugar macros start with `m4_', except `dnl' kept as is
+[# All the M4sugar macros start with 'm4_', except 'dnl' kept as is
 # for sake of simplicity.
 m4_pattern_forbid([^_?m4_])
 m4_pattern_forbid([^dnl$])
diff --git a/tests/autotest.at b/tests/autotest.at
index 71230df7..831a52b3 100644
--- a/tests/autotest.at
+++ b/tests/autotest.at
@@ -31,7 +31,7 @@ m4_define([AT_DATA_AUTOTEST],
 #                  [DIR = .])
 # --------------------------------------------------------------------
 # Create a new testsuite named NAME that runs a minimal Autotest test suite,
-# SUITE-CODE.  Do not use `testsuite' for NAME, or the log file it generates
+# SUITE-CODE.  Do not use 'testsuite' for NAME, or the log file it generates
 # will overwrite the log that the Autoconf test produces when managing
 # this test case.  STATUS, STDOUT, and STDERR pass directly to the AT_CHECK
 # that compiles the testsuite.  DIR can specify a particular subdirectory
@@ -802,7 +802,7 @@ AT_CHECK_AT_TEST([BS-BS-newline in command],
 conf
 ], [])])
 
-# A `^BS-BS-newline in command' test will run a command named `\'.  No, thanks.
+# A '^BS-BS-newline in command' test will run a command named '\'.  No, thanks.
 
 AT_CHECK_AT_TEST([BSx640-newline in command],
   [AT_CHECK([printf '%s\n' 
Auto"\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
@@ -863,7 +863,7 @@ AT_CLEANUP
 # Create a new test named TITLE that runs an Autotest test suite
 # comprised of a trivial test named TITLE-TO-TEST, which expands
 # to EXPANDED-TITLE-TO-TEST.  XFAIL-CONDITION passes verbatim to
-# AT_CHECK_AT.  Verify that `ok' prints at COLUMN.
+# AT_CHECK_AT.  Verify that 'ok' prints at COLUMN.
 m4_define([AT_CHECK_AT_TITLE],
 [AT_CHECK_AT([$1],
 [[
@@ -1057,7 +1057,7 @@ AT_CHECK([$CONFIG_SHELL ./micro-suite 1=2], [1], [], 
[ignore], [ignore])
 # Controlling where the testsuite is run.
 AT_CHECK_AT_TEST([Choosing where testsuite is run],
   [AT_CHECK([:])], [], [], [], [], [], [
-dnl AT_CHECK_AT_TEST tests the default of running in `.'.
+dnl AT_CHECK_AT_TEST tests the default of running in '.'.
 AT_CHECK([$CONFIG_SHELL ./micro-suite --clean])
 AT_CHECK([test -f micro-suite.log], [1])
 AT_CHECK([test -d micro-suite.dir], [1])
@@ -1609,8 +1609,8 @@ AT_SETUP([parallel autotest and signal handling])
 AT_SKIP_PARALLEL_TESTS
 
 # Goals:
-# (1) interrupt `./testsuite -jN'
-# (2) interrupt `make check TESTSUITEFLAGS=-jN'
+# (1) interrupt './testsuite -jN'
+# (2) interrupt 'make check TESTSUITEFLAGS=-jN'
 # (3) no trailing verbose/trace output
 # (4) exit status should be 128+signal
 
@@ -1675,7 +1675,7 @@ for signal in 2 15; do
   # turn off job control.
   # AT_CHECK([[grep '[iI]nterrupt[      ]' stderr]], [1])
 
-  # Ditto with `make' in the loop.
+  # Ditto with 'make' in the loop.
   # Explicitly setting TESTSUITEFLAGS to empty...
   AT_CHECK_MAKE([TESTSUITEFLAGS=], [], [1], [ignore], [stderr])
   AT_CHECK([grep 'bailing out' stderr], [], [ignore])
diff --git a/tests/base.at b/tests/base.at
index caf70ffa..9d6debbe 100644
--- a/tests/base.at
+++ b/tests/base.at
@@ -162,7 +162,7 @@ case $multi_test:$single_test in
   ..:. ) AS_EXIT(0);;
   ..:* ) AC_MSG_ERROR([DEFUN_ONCE is broken]);;
   *:.  ) AC_MSG_ERROR([DEFUN is broken (Wow, congrats!)]);;
-     * ) AC_MSG_ERROR([received `$multi_test:$single_test']);;
+     * ) AC_MSG_ERROR([received '$multi_test:$single_test']);;
 esac
 ]])
 
@@ -197,7 +197,7 @@ TEST
 
 case $inner_test in
   "" ) AS_EXIT(0);;
-  *  ) AC_MSG_ERROR([received `$inner_test']);;
+  *  ) AC_MSG_ERROR([received '$inner_test']);;
 esac
 ]])
 
@@ -595,7 +595,7 @@ AT_CLEANUP
 ## ---------------- ##
 
 # Make sure AC_CACHE_CHECK is silent with -q.
-# Also make sure we warn about cache id's not named with `_cv_'.
+# Also make sure we warn about cache id's not named with '_cv_'.
 
 AT_SETUP([AC_CACHE_CHECK])
 AT_KEYWORDS([CONFIG_SITE])
@@ -688,7 +688,7 @@ AC_DEFUN([AC_SHELL_TRUE],
                  (true) 2>/dev/null && my_cv_shell_true_works=yes
                  if test "x$my_cv_shell_true_works" = xyes; then
                    AC_DEFINE([TRUE_WORKS], [1],
-                             [Define if `true(1)' works properly.])
+                             [Define if 'true(1)' works properly.])
                  fi])
 ])
 AC_SHELL_TRUE
@@ -705,7 +705,7 @@ AC_DEFUN([AC_SHELL_TRUE],
                  (true) 2>/dev/null && my_cv_shell_true_works=yes])
  if test "x$my_cv_shell_true_works" = xyes; then
    AC_DEFINE([TRUE_WORKS], [1],
-             [Define if `true(1)' works properly.])
+             [Define if 'true(1)' works properly.])
  fi
 ])
 AC_SHELL_TRUE
diff --git a/tests/c.at b/tests/c.at
index 247774e2..d18bd5f5 100644
--- a/tests/c.at
+++ b/tests/c.at
@@ -31,8 +31,8 @@ AT_BANNER([C low level compiling/preprocessing macros.])
 AT_CHECK_CONFIGURE_AC([Object file extensions],
 [[AC_PROG_CC
 
-# As far as we know only `foo', `foo.exe' are possible executable,
-# and `foo.o', `foo.obj' are possible object files.  Autoconf must not
+# As far as we know only 'foo', 'foo.exe' are possible executable,
+# and 'foo.o', 'foo.obj' are possible object files.  Autoconf must not
 # know that, but it is OK for the test suite to take this into account.
 AS@&t@_CASE([$ac_exeext],
   ['' | '.exe'],
@@ -85,7 +85,7 @@ AC_C_VOLATILE
 # detect support for their respective keyword.
 case $GCC,$ac_cv_c_const,$ac_cv_c_typeof,$ac_cv_c_volatile in
  yes,*no*)
-   AC_MSG_ERROR([failed to detect `const', `typeof', or `volatile' support]);;
+   AC_MSG_ERROR([failed to detect 'const', 'typeof', or 'volatile' support]);;
 esac
 ]])
 
diff --git a/tests/compile.at b/tests/compile.at
index 798be241..c5a55679 100644
--- a/tests/compile.at
+++ b/tests/compile.at
@@ -291,11 +291,11 @@ AT_DATA([configure.ac],
 [[AC_INIT
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [return 0])],
              [],
-             [AC_MSG_ERROR([compiling `return 0' failed])])
+             [AC_MSG_ERROR([compiling 'return 0' failed])])
 
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [return 2])],
              [],
-             [AC_MSG_ERROR([compiling `return 2' failed])])
+             [AC_MSG_ERROR([compiling 'return 2' failed])])
 AC_OUTPUT
 ]])
 
@@ -316,17 +316,17 @@ AT_DATA([configure.ac],
 
 AC_RUN_IFELSE([AC_LANG_PROGRAM([], [return 0])],
              [],
-             [AC_MSG_ERROR([saw `return 0' as a failure])])
+             [AC_MSG_ERROR([saw 'return 0' as a failure])])
 
 AC_RUN_IFELSE([AC_LANG_PROGRAM([], [return 2])],
-             [AC_MSG_ERROR([saw `return 2' as a success])],
+             [AC_MSG_ERROR([saw 'return 2' as a success])],
              [estatus=$?
 test $estatus != 2 &&
   AC_MSG_ERROR([did not get 2 as exit status: $estatus])])
 
 # The old stinky one.
 AC_TRY_RUN([int main (void) { return 3; }],
-          [AC_MSG_ERROR([saw `return 3' as a success])],
+          [AC_MSG_ERROR([saw 'return 3' as a success])],
           [estatus=$?
 test $estatus != 3 &&
   AC_MSG_ERROR([did not get 3 as exit status: $estatus])])
@@ -335,7 +335,7 @@ AC_OUTPUT
 ]])
 
 AT_CHECK_AUTOCONF([], 0, [],
-[[configure.ac:14: warning: The macro `AC_TRY_RUN' is obsolete.
+[[configure.ac:14: warning: The macro 'AC_TRY_RUN' is obsolete.
 configure.ac:14: You should run autoupdate.
 general.m4: AC_TRY_RUN is expanded from...
 configure.ac:14: the top level
@@ -345,7 +345,7 @@ AT_CHECK_CONFIGURE([-q])
 AT_CLEANUP
 
 ## --------------------------  ##
-## Order of `rm' and actions.  ##
+## Order of 'rm' and actions.  ##
 ## --------------------------  ##
 
 AT_SETUP([Order of user actions and cleanup])
@@ -398,7 +398,7 @@ AT_CLEANUP
 
 AT_CHECK_MACRO([AC_TRY_LINK_FUNC],
 [AC_TRY_LINK_FUNC(printf,,
-                 [AC_MSG_ERROR([cannot find `printf'])])
+                 [AC_MSG_ERROR([cannot find 'printf'])])
 AC_TRY_LINK_FUNC(Be_doomed_if_your_libc_has_a_function_named_like_this,
                 [AC_MSG_ERROR([found a nonexistent function])])])
 
diff --git a/tests/data/ax_prog_cc_for_build_v18.m4 
b/tests/data/ax_prog_cc_for_build_v18.m4
index f7410d74..b139e9d4 100644
--- a/tests/data/ax_prog_cc_for_build_v18.m4
+++ b/tests/data/ax_prog_cc_for_build_v18.m4
@@ -19,7 +19,7 @@
 #   a compiler with an environment variable (like you do for standard CC).
 #
 #   It also sets BUILD_EXEEXT and BUILD_OBJEXT to the executable and object
-#   file extensions for the build platform, and GCC_FOR_BUILD to `yes' if
+#   file extensions for the build platform, and GCC_FOR_BUILD to 'yes' if
 #   the compiler we found is GCC. All these variables but GCC_FOR_BUILD are
 #   substituted in the Makefile.
 #
diff --git a/tests/data/gnulib_std_gnu11_2020_08_17.m4 
b/tests/data/gnulib_std_gnu11_2020_08_17.m4
index db833d82..da52cd6f 100644
--- a/tests/data/gnulib_std_gnu11_2020_08_17.m4
+++ b/tests/data/gnulib_std_gnu11_2020_08_17.m4
@@ -106,7 +106,7 @@ AC_LANG_POP(C)dnl
 # for (if not specified, a default list is used).  This just gives the
 # user an opportunity to specify an alternative search list for the C++
 # compiler.
-# aCC  HP-UX C++ compiler much better than `CC', so test before.
+# aCC  HP-UX C++ compiler much better than 'CC', so test before.
 # FCC   Fujitsu C++ compiler
 # KCC  KAI C++ compiler
 # RCC  Rational C++
@@ -161,7 +161,7 @@ AC_LANG_POP(C++)dnl
 # _AC_C_STD_TRY(STANDARD, TEST-PROLOGUE, TEST-BODY, OPTION-LIST,
 #              ACTION-IF-AVAILABLE, ACTION-IF-UNAVAILABLE)
 # --------------------------------------------------------------
-# Check whether the C compiler accepts features of STANDARD (e.g `c89', `c99')
+# Check whether the C compiler accepts features of STANDARD (e.g 'c89', 'c99')
 # by trying to compile a program of TEST-PROLOGUE and TEST-BODY.  If this 
fails,
 # try again with each compiler option in the space-separated OPTION-LIST; if 
one
 # helps, append it to CC.  If eventually successful, run ACTION-IF-AVAILABLE,
@@ -498,7 +498,7 @@ fi
 #                ACTION-IF-AVAILABLE, ACTION-IF-UNAVAILABLE)
 # ----------------------------------------------------------------
 # Check whether the C++ compiler accepts features of STANDARD (e.g
-# `cxx98', `cxx11') by trying to compile a program of TEST-PROLOGUE
+# 'cxx98', 'cxx11') by trying to compile a program of TEST-PROLOGUE
 # and TEST-BODY.  If this fails, try again with each compiler option
 # in the space-separated OPTION-LIST; if one helps, append it to CXX.
 # If eventually successful, run ACTION-IF-AVAILABLE, else
diff --git a/tests/fortran.at b/tests/fortran.at
index 6f8fa683..907cf6a3 100644
--- a/tests/fortran.at
+++ b/tests/fortran.at
@@ -169,8 +169,8 @@ AT_CLEANUP
 
 # We don't test the AC_F77_LIBRARY_LDFLAGS macro on its own because of
 # (autoconf.info)Fortran Compiler:
-#      The macros `AC_F77_DUMMY_MAIN' and `AC_FC_DUMMY_MAIN' or
-#    `AC_F77_MAIN' and `AC_FC_MAIN' are probably also necessary to link
+#      The macros 'AC_F77_DUMMY_MAIN' and 'AC_FC_DUMMY_MAIN' or
+#    'AC_F77_MAIN' and 'AC_FC_MAIN' are probably also necessary to link
 #    C/C++ with Fortran; see below.
 #
 # and we would need libtool to create shared libraries.
diff --git a/tests/local.at b/tests/local.at
index b5e68d37..4135ad9a 100644
--- a/tests/local.at
+++ b/tests/local.at
@@ -58,7 +58,7 @@ export MAKE
 
 # AT_CMP(FILE-1, FILE-2)
 # ----------------------
-# Check FILE-1 and FILE-2 for equality, like `cmp FILE-1 FILE-2'.
+# Check FILE-1 and FILE-2 for equality, like 'cmp FILE-1 FILE-2'.
 m4_define([AT_CMP],
 [m4_ifval([$2],, [m4_fatal([AT_CMP takes two arguments.])])[]dnl
 AT_CHECK([$at_diff "$1" "$2"])
@@ -71,7 +71,7 @@ AT_CHECK([$at_diff "$1" "$2"])
 
 # AT_CHECK_SHELL_SYNTAX(PROGRAM)
 # ------------------------------
-# If the shell handles `-n' well, use it to check the syntax of PROGRAM;
+# If the shell handles '-n' well, use it to check the syntax of PROGRAM;
 # otherwise, do nothing.  ksh93 -n also spits outs loads of warnings
 # about older constructs, but we don't care about the warnings.
 m4_define([AT_CHECK_SHELL_SYNTAX],
@@ -112,19 +112,19 @@ m4_define([AT_CHECK_PERL_SYNTAX],
 #
 # becomes
 #
-#  m4:script.4s:1: cannot open `foo': No such file or directory
+#  m4:script.4s:1: cannot open 'foo': No such file or directory
 #  autom4te: m4 failed with exit status: 1
 #
 # Also, this
 #
-#  configure.ac:6: warning: The macro `AC_LANG_SAVE' is obsolete.
+#  configure.ac:6: warning: The macro 'AC_LANG_SAVE' is obsolete.
 #  configure.ac:6: You should run autoupdate.
 #  ../../lib/autoconf/lang.m4:125: AC_LANG_SAVE is expanded from...
 #  configure.ac:6: the top level
 #
 # becomes
 #
-#  configure.ac:6: warning: The macro `AC_LANG_SAVE' is obsolete.
+#  configure.ac:6: warning: The macro 'AC_LANG_SAVE' is obsolete.
 #  configure.ac:6: You should run autoupdate.
 #  lang.m4: AC_LANG_SAVE is expanded from...
 #  configure.ac:6: the top level
@@ -137,8 +137,8 @@ m4_define([AT_CHECK_PERL_SYNTAX],
 #
 # and
 #     m4:(file):(line): Cannot open foo:
-# or  m4:(file):(line): include: cannot open `foo':
-# to  m4:(file):(line): cannot open `foo':
+# or  m4:(file):(line): include: cannot open [`']foo':
+# to  m4:(file):(line): cannot open 'foo':
 #
 # and
 #     autom4te: [^ ]m4
@@ -159,7 +159,7 @@ m4_case([$4], [], [], [ignore], [],
 [AT_CHECK([[mv stderr stderr-raw &&
    sed 's/^[^:]*m4[-.ex0-9]*: *\([^:]*:\) *\([0-9][0-9]*: \)/m4:\1\2/
        s/^\([^:]*:\) *\([0-9][0-9]*:\)[^:]*m4[-.ex0-9]*: /m4:\1\2 /
-       s/: C\(annot open \)\([^`:]*\):/: c\1`\2'\'':/
+       s/: C\(annot open \)\([^`'\'':]*\):/: c\1'\''\2'\'':/
        s/: include:\( cannot open\)/:\1/
        s/^autom4te: [^ ]*m4[.ex]* /autom4te: m4 /
        s/^autom4te: error: [^ ]*m4[.ex]* /autom4te: error: m4 /
@@ -273,7 +273,7 @@ fi
 # EXPECTED_TMPLS is a whitespace-separated list of template
 # definitions that should appear in the generated config.hin.
 # The stock definitions made by AC_INIT are also checked for.
-# If EXPECTED_TMPLS is the single word `ignore', or if the
+# If EXPECTED_TMPLS is the single word 'ignore', or if the
 # expected exit status is not 0, this test is skipped.
 m4_define([AT_CHECK_AUTOHEADER],
 [AT_CHECK_M4([autoheader $1], [$3], [$4], [$5])
@@ -309,7 +309,7 @@ AS_UNSET([config_h_in])
 #                    [EXIT-STATUS = 0],
 #                    [STDOUT = IGNORE], STDERR)
 # ---------------------------------------------
-# `abs_top_srcdir' is needed so that `./configure' finds install-sh.
+# 'abs_top_srcdir' is needed so that './configure' finds install-sh.
 # Using --srcdir is more expensive.
 m4_define([AT_CHECK_CONFIGURE],
 [AT_CAPTURE_FILE([config.log])[]dnl
@@ -331,16 +331,16 @@ m4_define([AT_CHECK_CONFIGURE],
 # commands in the pipe, so turn off tracing for these.
 #
 # Some tests might exit prematurely when they find a problem, in
-# which case `env-after' is probably missing.  Don't check it then.
+# which case 'env-after' is probably missing.  Don't check it then.
 #
-# Here are the variables `configure' may modify during execution:
+# Here are the variables 'configure' may modify during execution:
 # - ^as_
 #   M4sh's shell name space.
 # - ^ac_
 #   Autoconf's shell name space.
 # - prefix and exec_prefix
 #   are kept undefined (NONE) until AC_OUTPUT which then sets them to
-#   `/usr/local' and `${prefix}' for make.
+#   '/usr/local' and '${prefix}' for make.
 # - (host|build|target)(_(alias|cpu|vendor|os))?
 #   Set by AC_CANONICAL_(HOST|BUILD|TARGET).
 # - cross_compiling
@@ -354,7 +354,7 @@ m4_define([AT_CHECK_CONFIGURE],
 # - _|@|.[*#?$].|argv|ARGC|LINENO|OLDPWD|PIPESTATUS|RANDOM|SECONDS
 #   |START_TIME|ToD|_AST_FEATURES
 #   Some variables some shells use and change.
-#   `.[*#?$].' catches `$#' etc. which are displayed like this:
+#   '.[*#?$].' catches '$#' etc. which are displayed like this:
 #      | '!'=18186
 #      | '#'=0
 #      | '$'=6908
@@ -421,7 +421,7 @@ fi
 # AT_CONFIG_CMP(VAR-FILE-A, VAR-FILE-B, [EXTRA-VARIANCE])
 # -------------------------------------------------------
 # Check the outcomes of two configure runs for equality by comparing dumps of
-# their shell variables.  VAR-FILE-A and VAR-FILE-B are two `set'-style shell
+# their shell variables.  VAR-FILE-A and VAR-FILE-B are two 'set'-style shell
 # variable space dumps.
 #
 # We permit variance between runs in the following shell variables:
@@ -467,7 +467,7 @@ fi
 # empty.  (OTOH, cache variables indicate the result of the test even if they
 # are empty, so we have to be strict about them.)
 #
-# Lines that do not look like `foo=bar' are probably latter lines of
+# Lines that do not look like 'foo=bar' are probably latter lines of
 # multiline values; trim them.
 m4_define([AT_CONFIG_CMP],
 [for act_file in $1 $2
@@ -647,7 +647,7 @@ m4_define([AT_CHECK_AUTOUPDATE],
 # AT_CHECK_MAKE(MAKEARGS, DIRECTORY, EXIT-STATUS,
 #               [STDOUT = IGNORE], [STDERR = IGNORE])
 # ---------------------------------------------------------------
-# Run make in DIRECTORY (default `.'), passing MAKEARGS on the command
+# Run make in DIRECTORY (default '.'), passing MAKEARGS on the command
 # line.  EXIT-STATUS, STDOUT, and STDERR are as for AT_CHECK.
 # The environment variable MAKE is honored if present.
 # The environment variable MAKEFLAGS is *cleared*.
@@ -728,15 +728,15 @@ AT_CLEANUP
 # list of modifiers to how the test is carried out.  Currently
 # the following modifiers are defined:
 #
-#   - `no-cross': Don't test this macro in cross-compilation mode.
+#   - 'no-cross': Don't test this macro in cross-compilation mode.
 #     This is for macros that use AC_RUN_IFELSE, and therefore, when
-#     cross-compiling, they either crash or give a `best guess' answer
+#     cross-compiling, they either crash or give a 'best guess' answer
 #     that may be wrong.
 #
-#   - `cxx_cv_varies:NAME': The value of the cache variable ac_cv_NAME
+#   - 'cxx_cv_varies:NAME': The value of the cache variable ac_cv_NAME
 #     may legitimately vary between the C tests and the C++ tests.
 #
-#   - `cxx_define_varies:NAME' The value of the AC_DEFINEd macro NAME
+#   - 'cxx_define_varies:NAME' The value of the AC_DEFINEd macro NAME
 #     may legitimately vary between the C tests and the C++ tests.
 m4_define([AT_CHECK_MACRO],
 [AT_SETUP([$1])
@@ -880,8 +880,8 @@ AT_CLEANUP
 # _AT_FILTER_CXX_CV_VARIES(TEST-PARAMETERS)
 # ---------------------------------------------
 # Subroutine of AT_CHECK_MACRO that expands to a sequence of
-# zero or more `vary:NAME' tokens, one for each occurrence of
-# `cxx_cv_varies:NAME' in TEST-PARAMETERS.
+# zero or more 'vary:NAME' tokens, one for each occurrence of
+# 'cxx_cv_varies:NAME' in TEST-PARAMETERS.
 m4_define([_AT_FILTER_CXX_CV_VARIES],
 [m4_map_args_w([$1], [_AT_FILTER_CXX_CV_VARY(], [)], [ ])])
 
@@ -893,8 +893,8 @@ m4_define([_AT_FILTER_CXX_CV_VARY],
 # _AT_FILTER_CXX_DEFINE_VARIES(TEST-PARAMETERS)
 # ---------------------------------------------
 # Subroutine of AT_CHECK_MACRO that expands to a sequence of
-# zero or more `vary:NAME' tokens, one for each occurrence of
-# `cxx_define_varies:NAME' in TEST-PARAMETERS.
+# zero or more 'vary:NAME' tokens, one for each occurrence of
+# 'cxx_define_varies:NAME' in TEST-PARAMETERS.
 m4_define([_AT_FILTER_CXX_DEFINE_VARIES],
 [m4_map_args_w([$1], [_AT_FILTER_CXX_DEFINE_VARY(], [)], [ ])])
 
diff --git a/tests/m4sh.at b/tests/m4sh.at
index 63bdd396..a20b8b13 100644
--- a/tests/m4sh.at
+++ b/tests/m4sh.at
@@ -252,9 +252,9 @@ sed 's/__LINENO__/$''LINENO/g;s/__OLINE__/__''oline__/g' 
$1.tas >$1.as
 AT_CHECK([autom4te -l m4sh $1.as -o $1])
 ])# AT_DATA_LINENO
 
-# `_oline_', once processed and ran, produces our reference.
+# '_oline_', once processed and ran, produces our reference.
 # We check that we find ourselves by looking at a string which is
-# available only in the original script: `_oline_'.
+# available only in the original script: '_oline_'.
 AT_DATA_LINENO([reference], [true], [__OLINE__], [_oline__])
 AT_CHECK([./reference], 0, [stdout])
 
@@ -419,8 +419,8 @@ AT_KEYWORDS([m4sh])
 AT_DATA_M4SH([script.as],
 [[AS_INIT
 
-# The EXPR variant is allowed to fail if `expr' was considered as too
-# weak for us, in which case `as_expr=false'.
+# The EXPR variant is allowed to fail if 'expr' was considered as too
+# weak for us, in which case 'as_expr=false'.
 m4_define([DIRNAME_TEST],
 [dir=`AS_DIRNAME([$1])`
 test "$dir" = "$2" || (test -n "$3" && test "$dir" = "$3") ||
@@ -645,7 +645,7 @@ AT_SETUP([Redefining AS@&t@_ECHO internals])
 # this file to exist anyway.
 AT_DATA([config.hin])
 
-# Defining a macro named `s' or `n' should not affect AS_ECHO or
+# Defining a macro named 's' or 'n' should not affect AS_ECHO or
 # macros that use it.
 
 AT_CONFIGURE_AC(
@@ -700,7 +700,7 @@ config.status: creating config.h
 AT_CHECK_ENV
 rm config.h
 
-# However, defining a macro named `printf' _is_ expected to affect
+# However, defining a macro named 'printf' _is_ expected to affect
 # the functioning of AS_ECHO.
 
 AT_CONFIGURE_AC(
@@ -940,7 +940,7 @@ AT_CLEANUP
 ## ----------------------------- ##
 
 # According to https://www.in-ulm.de/~mascheck/bourne/, all shells with
-# functions also support `[!...]'.  But `[^...]' is not universally supported.
+# functions also support '[!...]'.  But '[^...]' is not universally supported.
 
 AT_SETUP([Negated classes in globbing])
 AT_KEYWORDS([m4sh])
@@ -950,11 +950,11 @@ AT_DATA_M4SH([script.as],
 
 case 'with!two!bangs' in
   *[[!a-z]]*) ;;
-           *) AS_ERROR([[`*[!a-z]*' didn't match `with!two!bangs']]);;
+           *) AS_ERROR([['*[!a-z]*' didn't match 'with!two!bangs']]);;
 esac
 
 case without in
-  *[[!a-z]]*) AS_ERROR([[`*[!a-z]*' matched `without']]);;
+  *[[!a-z]]*) AS_ERROR([['*[!a-z]*' matched 'without']]);;
 esac
 ]])
 
@@ -968,7 +968,7 @@ AT_CLEANUP
 ## ---------------------------- ##
 
 # According to https://www.in-ulm.de/~mascheck/bourne/, all shells with
-# functions also support `${a:-b}'.
+# functions also support '${a:-b}'.
 
 AT_SETUP([Null variable substitution])
 AT_KEYWORDS([m4sh])
@@ -1501,7 +1501,7 @@ AS_CASE([$[1]]m4_for([i], [1], ]limit[, [], [, i, echo 
i]))
 AS_CASE([$[1]]m4_for([i], [1], ]limit[, [], [, i, echo i]), [echo default])
 ]])
 
-dnl Add --force so autom4te doesn't think `script' is still up to date.
+dnl Add --force so autom4te doesn't think 'script' is still up to date.
 AT_CHECK_M4SH([--force])
 AT_CHECK([$CONFIG_SHELL ./script 1], [0], [[1
 1
diff --git a/tests/m4sugar.at b/tests/m4sugar.at
index c38d9dde..60f00e59 100644
--- a/tests/m4sugar.at
+++ b/tests/m4sugar.at
@@ -670,7 +670,7 @@ a
 c
 post
 ]],
-[[script.4s:15: warning: m4@&t@_require: `a' was expanded before it was 
required
+[[script.4s:15: warning: m4@&t@_require: 'a' was expanded before it was 
required
 script.4s:15: 
https://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required
 script.4s:5: b is expanded from...
 script.4s:6: c is expanded from...
@@ -1082,7 +1082,7 @@ str
 ]])
 
 AT_CHECK_M4SUGAR([-o-], 0, [[a a b
-]], [[script.4s:3: warning: m4@&t@_append_uniq: `a b' contains ` '
+]], [[script.4s:3: warning: m4@&t@_append_uniq: 'a b' contains ' '
 ]])
 
 AT_CLEANUP
@@ -1157,7 +1157,7 @@ esac
 case b in
   *[)] echo active, ;;
 esac])
-dnl unbalanced underquoted `)', but we manage anyway (gasp!)
+dnl unbalanced underquoted ')', but we manage anyway (gasp!)
 m4_expand([case c in #(
   *) echo active, ;;
 esac
@@ -1345,10 +1345,10 @@ AT_CLEANUP
 
 AT_SETUP([Standard regular expressions])
 
-# AT_CHECK_M4RE(RE-NAME, TEXT, INTENT = `ok' | `')
+# AT_CHECK_M4RE(RE-NAME, TEXT, INTENT = 'ok' | '')
 # ------------------------------------------------
 # Check whether RE-NAME (a macro whose definition is a regular expression)
-# matches TEXT.  INTENT = `ok' if the match should succeed or else empty.
+# matches TEXT.  INTENT = 'ok' if the match should succeed or else empty.
 m4_define([AT_CHECK_M4RE],
 [AT_CHECK_M4SUGAR_TEXT(
 [[m4_bregexp([$2], ^m4_defn([$1])$, [ok])
diff --git a/tests/semantics.at b/tests/semantics.at
index 7a5f83a8..cce44b4e 100644
--- a/tests/semantics.at
+++ b/tests/semantics.at
@@ -389,7 +389,7 @@ AT_CONFIGURE_AC([[AC_CHECK_HEADERS([header2.h], [], [], 
[-])]])
 AT_CHECK_AUTOCONF([], 0, [],
 [[configure.ac:4: warning: Checking for headers with the preprocessor is
 configure.ac:4: deprecated. Specify prerequisite code to AC_CHECK_HEADER
-configure.ac:4: instead of using fourth argument `-'. (Many headers need
+configure.ac:4: instead of using fourth argument '-'. (Many headers need
 configure.ac:4: no prerequisites. If you truly need to test whether
 configure.ac:4: something passes the preprocessor but not the compiler,
 configure.ac:4: use AC_PREPROC_IFELSE.)
@@ -451,17 +451,17 @@ AT_CLEANUP
 AT_CHECK_MACRO([AC_CHECK_MEMBER],
 [[AC_CHECK_MEMBER([struct yes_s.yes],
                  [AC_DEFINE([HAVE_STRUCT_YES_S_YES], [1],
-                            [Define to 1 if `yes' is a member of `struct 
yes_s'.])],,
+                            [Define to 1 if 'yes' is a member of 'struct 
yes_s'.])],,
                   [struct sub { int x; };
                    struct yes_s { int yes; struct sub substruct; };])
   AC_CHECK_MEMBER([struct yes_s.no],
                  [AC_DEFINE([HAVE_STRUCT_YES_S_NO], [1],
-                            [Define to 1 if `no' is a member of `struct 
yes_s'.])],,
+                            [Define to 1 if 'no' is a member of 'struct 
yes_s'.])],,
                   [struct sub { int x; };
                    struct yes_s { int yes; struct sub substruct; };])
   AC_CHECK_MEMBER([struct yes_s.substruct],
                  [AC_DEFINE([HAVE_STRUCT_YES_S_SUBSTRUCT], [1],
-                            [Define to 1 if `substruct' is a member of `struct 
yes_s'.])],,
+                            [Define to 1 if 'substruct' is a member of 'struct 
yes_s'.])],,
                   [struct sub { int x; };
                    struct yes_s { int yes; struct sub substruct; };])]],
 [AT_CHECK_DEFINES(
@@ -557,7 +557,7 @@ AT_CHECK([[grep "#define SIZEOF_INT_P [1-9]" config.h]],
 # --------------
 # Check that it performs the correct actions.
 # Must define HAVE_STRUCT_YES_S, HAVE_INT, but not HAVE_STRUCT_NO_S.
-# `int' and `struct yes_s' are both checked to test both the compiler
+# 'int' and 'struct yes_s' are both checked to test both the compiler
 # builtin types, and defined types.
 AT_CHECK_MACRO([AC_CHECK_TYPES],
 [[AC_CHECK_TYPES([int, struct yes_s, struct no_s],,,
@@ -608,7 +608,7 @@ AT_CLEANUP
 # AC_CHECK_FILES
 # --------------
 # FIXME: To really test HAVE_AC_EXISTS2 and HAVE_AC_MISSING2 we need to
-# open AH_TEMPLATE to `configure.ac', which is not yet the case.
+# open AH_TEMPLATE to 'configure.ac', which is not yet the case.
 # Don't use AT_CHECK_MACRO for this one because AC_CHECK_FILES can't be
 # used when cross compiling.
 
@@ -633,8 +633,8 @@ rm at-exists1 at-exists2]],
 
 # AT_CHECK_PROGS_PREPARE
 # ----------------------
-# Create a sub directory `path' with 6 subdirs which all 7 contain
-# an executable `tool'. `6' contains a `better' tool.
+# Create a sub directory 'path' with 6 subdirs which all 7 contain
+# an executable 'tool'. '6' contains a 'better' tool.
 m4_define([AT_CHECK_PROGS_PREPARE],
 [mkdir path
 
@@ -1023,7 +1023,7 @@ $1([dn@&t@l
 AT_CHECK_AUTOCONF([], [0], [],
 [configure.ac:6: warning: whitespace-separated list contains macros;
 configure.ac:6: in a future version of Autoconf they will not be expanded
-configure.ac:6: note: `dn@&t@l' is a macro
+configure.ac:6: note: 'dn@&t@l' is a macro
 functions.m4: $1 is expanded from...
 configure.ac:6: the top level
 ])
@@ -1052,7 +1052,7 @@ $1([dn@&t@l
 AT_CHECK_AUTOCONF([], [0], [],
 [configure.ac:8: warning: whitespace-separated list contains macros;
 configure.ac:8: in a future version of Autoconf they will not be expanded
-configure.ac:8: note: `dn@&t@l' is a macro
+configure.ac:8: note: 'dn@&t@l' is a macro
 functions.m4: $1 is expanded from...
 configure.ac:8: the top level
 configure.ac:8: warning: $1($fns): you should use literals
@@ -1084,7 +1084,7 @@ $1([dn@&t@l
 AT_CHECK_AUTOCONF([], [0], [],
 [configure.ac:6: warning: whitespace-separated list contains macros;
 configure.ac:6: in a future version of Autoconf they will not be expanded
-configure.ac:6: note: `dn@&t@l' is a macro
+configure.ac:6: note: 'dn@&t@l' is a macro
 headers.m4: $1 is expanded from...
 configure.ac:6: the top level
 ])
@@ -1123,7 +1123,7 @@ $1([dn@&t@l
 AT_CHECK_AUTOCONF([], [0], [],
 [configure.ac:8: warning: whitespace-separated list contains macros;
 configure.ac:8: in a future version of Autoconf they will not be expanded
-configure.ac:8: note: `dn@&t@l' is a macro
+configure.ac:8: note: 'dn@&t@l' is a macro
 headers.m4: $1 is expanded from...
 configure.ac:8: the top level
 configure.ac:8: warning: $1($hs): you should use literals
@@ -1170,7 +1170,7 @@ AC_CHECK_FILES([dn@&t@l
 AT_CHECK_AUTOCONF([], [0], [],
 [configure.ac:6: warning: whitespace-separated list contains macros;
 configure.ac:6: in a future version of Autoconf they will not be expanded
-configure.ac:6: note: `dn@&t@l' is a macro
+configure.ac:6: note: 'dn@&t@l' is a macro
 general.m4: AC_CHECK_FILES is expanded from...
 configure.ac:6: the top level
 ])
@@ -1200,7 +1200,7 @@ configure.ac:6:AC_CONFIG_MACRO_DIR_TRACE:d_blurf
 ],
 [configure.ac:6: warning: whitespace-separated list contains macros;
 configure.ac:6: in a future version of Autoconf they will not be expanded
-configure.ac:6: note: `dn@&t@l' is a macro
+configure.ac:6: note: 'dn@&t@l' is a macro
 general.m4: AC_CONFIG_MACRO_DIRS is expanded from...
 configure.ac:6: the top level
 ])
@@ -1228,7 +1228,7 @@ AC_CONFIG_SUBDIRS([dn@&t@l
 AT_CHECK_AUTOCONF([], [0], [],
 [configure.ac:6: warning: whitespace-separated list contains macros;
 configure.ac:6: in a future version of Autoconf they will not be expanded
-configure.ac:6: note: `dn@&t@l' is a macro
+configure.ac:6: note: 'dn@&t@l' is a macro
 status.m4: AC_CONFIG_SUBDIRS is expanded from...
 configure.ac:6: the top level
 ])
diff --git a/tests/suite.at b/tests/suite.at
index 3976478e..2e5a0225 100644
--- a/tests/suite.at
+++ b/tests/suite.at
@@ -20,7 +20,7 @@
 # the most selective to the easiest.
 
 # The executables.
-# Even the tests on M4sugar and M4sh use `autoconf', so check it first.
+# Even the tests on M4sugar and M4sh use 'autoconf', so check it first.
 m4_include([tools.at])
 
 # M4sugar.
@@ -38,7 +38,7 @@ m4_include([base.at])
 # Testing config.status
 # ---------------------
 # Actually should be named config.status.at but I fear problems with
-# the name.  Does no `checking ...' at all, but exercises only code
+# the name.  Does no 'checking ...' at all, but exercises only code
 # which following section use too.  Hence, run it first.
 m4_include([torture.at])
 
@@ -60,7 +60,7 @@ m4_include([acgo.at])
 m4_include([semantics.at])
 
 # Blind testing the macros.
-# Include them as is suggested for a `configure.ac', as looking for
+# Include them as is suggested for a 'configure.ac', as looking for
 # for types requires looking for headers etc.
 m4_include([acgeneral.at])
 m4_include([acstatus.at])
diff --git a/tests/tools.at b/tests/tools.at
index 08f6b42e..77d9c1e6 100644
--- a/tests/tools.at
+++ b/tests/tools.at
@@ -23,9 +23,9 @@ AT_BANNER([Executables (autoheader, autoupdate...).])
 ## Syntax of the shell scripts.  ##
 ## ----------------------------- ##
 
-# We use `/bin/sh -n script' to check that there are no syntax errors
+# We use '/bin/sh -n script' to check that there are no syntax errors
 # in the scripts.  Although incredible, there are /bin/sh that go into
-# endless loops with `-n', e.g., SunOS's:
+# endless loops with '-n', e.g., SunOS's:
 #
 #   $ uname -a
 #   SunOS ondine 4.1.3 2 sun4m unknown
@@ -40,15 +40,15 @@ AT_BANNER([Executables (autoheader, autoupdate...).])
 #   $ time sh -nx endless.sh
 #   ^Csh -nx endless.sh  3,67s user 0,03s system 63% cpu 5,868 total
 #
-# So before using `/bin/sh -n' to check our scripts, we first check
-# that `/bin/sh -n' is not broken to death.
+# So before using '/bin/sh -n' to check our scripts, we first check
+# that '/bin/sh -n' is not broken to death.
 
 AT_SETUP([Syntax of the shell scripts])
 
 AT_CHECK([test "$SHELL_N" != none || exit 77])
 
 # Specify the absolute name of the tool, as some shells don't honor PATH when
-# running `sh PROG'.
+# running 'sh PROG'.
 
 AT_CHECK_SHELL_SYNTAX(["$abs_top_builddir/bin/autoconf"])
 AT_CHECK_SHELL_SYNTAX(["$abs_top_builddir/tests/autoconf"])
@@ -346,9 +346,9 @@ AT_CHECK_AUTOCONF([[-t define | sed -n '$p']],
 [[configure.ac:1:define:active:ACTIVE
 ]])
 
-# FIXME: Without `$1' the following test dies.  Groumphf, once again to
+# FIXME: Without '$1' the following test dies.  Groumphf, once again to
 # dive into obscure feature interaction...
-# Note that using `-i' means we need the *.m4 files, not the *.m4f files,
+# Note that using '-i' means we need the *.m4 files, not the *.m4f files,
 # hence we need srcdir, not builddir.
 AT_CHECK_AUTOCONF([[-t define:'$1' -i| sed -n '$p']],
         0,
@@ -510,7 +510,7 @@ NOT_FORBIDDEN FORBIDDEN FORBIDDEN_NOT
 # Test Autoconf's patterns.
 AS_THIS_IS_INVALID and _AS_THIS_IS_INVALID_TOO
 BUT_AZ_THIS_IS_NOT ALTHOUGH_AS_THIS_IS
-# This is legal, although there is `AS_DEFINE' in there.
+# This is legal, although there is 'AS_DEFINE' in there.
 BAS_DEFINE
 # AS_THIS_IS_A_COMMENT so just shut up.
 It would be very bad if Autoconf forgot to expand [AS_]INIT!
@@ -769,7 +769,7 @@ AT_DATA([acconfig.h],
 ]])
 
 
-# 1. Check that `acconfig.h' is still honored.
+# 1. Check that 'acconfig.h' is still honored.
 AT_DATA([configure.ac],
 [[AC_INIT
 AC_CONFIG_HEADERS(config.h:config.hin)
@@ -839,7 +839,7 @@ AC_DEFINE([ANT], [@], [The Ant in a h@t.])
 ]])
 
 
-# Yes, that's right: the `middle' part of `acconfig.h' is still before
+# Yes, that's right: the 'middle' part of 'acconfig.h' is still before
 # the AH_TOP part.  But so what, you're not supposed to use the two
 # together.
 # Ignore STDERR which is the longish complaint against autoheader junk
@@ -980,10 +980,10 @@ AC_CONFIG_COMMANDS([default],[echo $fubar],[fubar=$fubar])
 AC_OUTPUT
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 AT_CHECK_AUTOUPDATE
 AT_CHECK([cat configure.ac], 0, [expout])
-# Checking that `autoupdate' is idempotent
+# Checking that 'autoupdate' is idempotent
 AT_CHECK_AUTOUPDATE
 AT_CHECK([cat configure.ac], 0, [expout])
 
@@ -1005,7 +1005,7 @@ AT_DATA([dst1], dst1
 AT_DATA([dst2], dst2
 )
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 AT_CHECK_AUTOUPDATE([], 0, [], ignore)
 
 # The replacement for AC_LINK_FILES includes a forced -Wobsolete
@@ -1031,7 +1031,7 @@ AT_CLEANUP
 # ----------------------
 AT_SETUP([autoupdating AC_PREREQ])
 
-# Produce `AC_PREREQ(<AUTOUPDATE VERSION>)'.
+# Produce 'AC_PREREQ(<AUTOUPDATE VERSION>)'.
 AT_CHECK([autoupdate --version | sed 's/.*) //;q'], 0, [stdout])
 autoupdate_version=`cat stdout`
 [echo "AC_PREREQ([$autoupdate_version])" >expout]
@@ -1063,7 +1063,7 @@ AC_CONFIG_HEADERS([config.h])
 AC_OUTPUT
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 AT_CHECK_AUTOUPDATE
 
 # autoupdate does not replace AU_DEFUNs/AU_ALIASes defined by
@@ -1116,7 +1116,7 @@ NEW([0, 0], [0])
 AC_OUTPUT
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 AT_CHECK_AUTOUPDATE
 AT_CHECK_AUTOCONF
 AT_CHECK_CONFIGURE
@@ -1141,7 +1141,7 @@ AC_TRY_COMPILE([], [choke me], [echo bogus1],
 AC_OUTPUT
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 AT_CHECK_AUTOUPDATE
 AT_CHECK([grep changequote configure.ac], [1])
 AT_CHECK([grep TRY_COMPILE configure.ac], [1])
@@ -1161,7 +1161,7 @@ AC_ARG_ENABLE([foo], [AC_HELP_STRING([--enable-foo], [foo 
bar])], [:], [:])
 AC_OUTPUT
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 AT_CHECK_AUTOUPDATE([], [], [], [ignore])
 AT_CHECK_AUTOCONF
 AT_CHECK_CONFIGURE([], [], [], [ignore])
@@ -1198,7 +1198,7 @@ AC_MSG_RESULT_UNQUOTED([`echo done`])
 AC_OUTPUT([foo])
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 AT_CHECK_AUTOUPDATE([], [], [], [ignore])
 AT_CHECK_AUTOCONF
 AT_CHECK_CONFIGURE([], [], [], [ignore])
@@ -1223,7 +1223,7 @@ m4@&t@_popdef([AC_MSG_RESULT_UNQUOTED])
 AC_OUTPUT
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 AT_CHECK_AUTOUPDATE([], [], [], [ignore])
 AT_CHECK([grep changequote configure.ac], [1])
 AT_CHECK([grep [pushdef.*AC_MSG_RESULT_UNQUOTED] configure.ac], [0], [ignore])
@@ -1250,7 +1250,7 @@ MACRO
 AC_OUTPUT
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 AT_CHECK_AUTOUPDATE([], [], [], [ignore])
 AT_CHECK_AUTOCONF
 AT_CHECK_CONFIGURE([], [], [], [ignore])
@@ -1276,7 +1276,7 @@ AC_TRY_COMPILE([#include <stdio.h>
 AC_OUTPUT
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 AT_CHECK_AUTOUPDATE([], [], [], [ignore])
 AT_CHECK_AUTOCONF
 AT_CHECK([grep MACRO configure], [1])
@@ -1298,7 +1298,7 @@ AC_LANG_RESTORE
 AC_OUTPUT
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 
 # Both the autoupdate and autoconf invocations will complain about
 # AC_LANG_SAVE being obsolete, because autoupdate cannot replace
@@ -1327,7 +1327,7 @@ echo AC_FOREACH([myvar], [1 2 3], [' myvar'])OLD
 AC_OUTPUT
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 # AC_FOREACH is replaced with an m4sugar macro, so we must make sure
 # the m4sugar macro wasn't expanded.
 AT_CHECK_AUTOUPDATE
@@ -1364,7 +1364,7 @@ AT_CHECK_AUTOCONF([-Werror], 1, [],
 general.m4: AC_OBSOLETE is expanded from...
 aclocal.m4:1: OLD is expanded from...
 configure.ac:2: the top level
-configure.ac:2: warning: The macro `AC_OBSOLETE' is obsolete.
+configure.ac:2: warning: The macro 'AC_OBSOLETE' is obsolete.
 configure.ac:2: You should run autoupdate.
 general.m4: AC_OBSOLETE is expanded from...
 aclocal.m4:1: OLD is expanded from...
@@ -1414,7 +1414,7 @@ AC_WARNING([funny punctu&tion])
 AC_OUTPUT
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 # AC_DIAGNOSE and AC_WARNING are replaced with m4sugar macros, so we
 # must make sure the m4sugar macros weren't expanded.
 AT_CHECK_AUTOUPDATE
@@ -1442,7 +1442,7 @@ AC_FATAL([what did you do this time])
 AC_OUTPUT
 ]])
 
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 # AC_FATAL is replaced with a m4sugar macro, so we
 # must make sure the m4sugar macro wasn't expanded.
 AT_CHECK_AUTOUPDATE
@@ -1487,7 +1487,7 @@ AC_DEFUN([AC_UNCHANGED_MACRO], [echo one])
 ]])
 cp m4/stuff.m4 aclocal/stuff.m4
 AT_CHECK([$ACLOCAL -I aclocal], [0], [ignore], [ignore])
-# Checking `autoupdate'.
+# Checking 'autoupdate'.
 AT_CHECK_AUTOUPDATE
 AT_CHECK([$ACLOCAL -I m4], [0], [ignore], [ignore])
 AT_CHECK_AUTOUPDATE
@@ -1525,7 +1525,7 @@ AT_DATA([Makefile.am],
 [[AUTOMAKE_OPTIONS = foreign
 ]])
 
-$sleep # `aclocal.m4' should be strictly younger than its inputs
+$sleep # 'aclocal.m4' should be strictly younger than its inputs
 
 # If Autoconf is too old, or the user has turned caching off, skip:
 AT_CHECK([$ACLOCAL || { ret=$?; test $ret -eq 63 && ret=77; exit $ret; }],
@@ -1537,7 +1537,7 @@ AT_CHECK([autoconf])
 # comparing the old and new requests is a good place to start debugging:
 sort autom4te.cache/requests >old-requests
 echo newer >newer
-$sleep # if `configure' is regenerated, we want it to be strictly newer,
+$sleep # if 'configure' is regenerated, we want it to be strictly newer,
        # to catch the error consistently.
 AT_CHECK([$ACLOCAL], [],[], [ignore])
 AT_CHECK([automake --no-force --add-missing], [], [], [ignore])
diff --git a/tests/torture.at b/tests/torture.at
index 03f3d04f..8bd0d013 100644
--- a/tests/torture.at
+++ b/tests/torture.at
@@ -107,9 +107,9 @@ AT_CHECK_CONFIGURE([--config-cache -q])
 AT_CHECK([cat file], [], [`$1'
 ])
 
-# Testing --recheck: 1. have the environment `forget' about PRECIOUS.
+# Testing --recheck: 1. have the environment 'forget' about PRECIOUS.
 unset precious
-# 2. Rerun config.status to recreate `file'.
+# 2. Rerun config.status to recreate 'file'.
 AT_CHECK([./config.status --recheck], [], [ignore])
 AT_CHECK([./config.status], [], [ignore])
 # 3. Check that file contains the old value of PRECIOUS.
@@ -129,7 +129,7 @@ AT_CHECK_CONFIGURE([--config-cache], [m4_default([$3], 
[1])], [stdout], [stderr]
 AT_SETUP([AC_ARG_VAR])
 
 # We don't want to run this test if this shell doesn't support
-# `unset'.
+# 'unset'.
 AT_CHECK([
 if (FOO=FOO; unset FOO) >/dev/null 2>&1; then
   exit 0
@@ -228,7 +228,7 @@ AT_CHECK_AUTOCONF
 # ------------------------------------------------------------------
 # Check that THING and var-THING (which uses variables in AC_CONFIG_THING)
 # are properly created, with the right content.
-# Use `grep OK' instead of a simple `cat' to avoid banners such as in
+# Use 'grep OK' instead of a simple 'cat' to avoid banners such as in
 # AC_CONFIG_HEADERS.
 m4_define([AT_CHECK_CONFIG_CREATION],
 [AT_CHECK_CONFIGURE([what_to_test=$1])
@@ -254,7 +254,7 @@ AT_CHECK([grep OK var-$1], [], [OK
 # --------------------------------------------------------------------------
 # Check that THING and var-THING (which uses variables in AC_CONFIG_THING)
 # are properly created, with the right content.
-# Use `grep OK' instead of a simple `cat' to avoid banners such as in
+# Use 'grep OK' instead of a simple 'cat' to avoid banners such as in
 # AC_CONFIG_HEADERS.
 m4_define([AT_CHECK_CONFIG_CREATION_NOWRITE],
 [AT_CHECK_CONFIGURE([what_to_test=$1])
@@ -331,7 +331,7 @@ AT_CHECK_CONFIG_CREATION_NOWRITE(command)
 # Create a link
 AT_CHECK_CONFIG_CREATION_NOWRITE(link)
 
-# Check that no use of `ac_write_fail' escaped into config.status
+# Check that no use of 'ac_write_fail' escaped into config.status
 AT_CHECK([grep ac_write_fail config.status], [1])
 
 # Check that --file and --header accept funny file names
@@ -410,13 +410,13 @@ mkdir build
 AT_CAPTURE_FILE([build/config.log])[]dnl
 cd build
 AT_CHECK([../configure], [1], [ignore],
-[[config.status: error: cannot find input file: `nonexistent.in'
+[[config.status: error: cannot find input file: 'nonexistent.in'
 ]])
 # Make sure that the output file doesn't exist
 AT_CHECK([test -f nonexistent], 1)
 cd ..
 AT_CHECK_CONFIGURE([], [1], [],
-[[config.status: error: cannot find input file: `nonexistent.in'
+[[config.status: error: cannot find input file: 'nonexistent.in'
 ]])
 # Make sure that the output file doesn't exist
 AT_CHECK([test -f nonexistent], 1)
@@ -430,14 +430,14 @@ AT_CLEANUP
 ## configure invocation.  ##
 ## ---------------------- ##
 
-# Check that `configure' and `config.status' honor their interface.
+# Check that 'configure' and 'config.status' honor their interface.
 #
-# We run `./configure one=val1 --enable-two=val2 --with-three=val3'
-# and verify that (i) `configure' correctly receives the arguments,
-# (ii) correctly passes them to `config.status', which we check by
-# running `config.status --recheck', (iii) correctly passes them
+# We run './configure one=val1 --enable-two=val2 --with-three=val3'
+# and verify that (i) 'configure' correctly receives the arguments,
+# (ii) correctly passes them to 'config.status', which we check by
+# running 'config.status --recheck', (iii) correctly passes them
 # to sub-configure scripts, and (iv) correctly reproduces them with
-# `config.status --config'.
+# 'config.status --config'.
 
 AT_SETUP([configure invocation])
 
@@ -524,10 +524,10 @@ AT_CLEANUP
 
 
 ## -------------------------------------------- ##
-## Check that `#define' templates are honored.  ##
+## Check that '#define' templates are honored.  ##
 ## -------------------------------------------- ##
 
-# Use various forms of `#define' templates, and make sure there are no
+# Use various forms of '#define' templates, and make sure there are no
 # problems when a symbol is prefix of another.
 
 AT_SETUP([@%:@define header templates])
@@ -644,7 +644,7 @@ AT_DATA([expout],
 [[-DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" 
-DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -Dfoo=toto 
-Dbar=tata -Dbaz=titi -Dfubar=tutu -Da=A -Daaa=AAA -Daa=AA 
-Dmultiline=line1line2line3\ line4 -Dmultiline_args\(ARG1,\ ARG2\)=ARG2\ ARG1 
-Dpaste\(a,b\)=a\#\#b
 ]])
 
-# Because we strip trailing spaces in `testsuite' we can't leave one in
+# Because we strip trailing spaces in 'testsuite' we can't leave one in
 # expout, hence nuke the one left by AC_OUTPUT_MAKE_DEFS.
 AT_CHECK([sed -e 's/ $//' defs], 0, expout)
 
@@ -659,7 +659,7 @@ AT_CLEANUP
 ## Require 100 AC_DEFINE and AC_SUBST and AC_SUBST_FILE with a significantly
 ## big value.  This is mostly to check that Autoconf produces portable sed
 ## scripts in config.status.  sed is used to skip the first two lines
-## `Generated by ...'.
+## 'Generated by ...'.
 
 # We use m4_for many times.
 m4_pattern_allow([^m4_for$])
@@ -673,7 +673,7 @@ m4_define([AT_BIG_VALUE],
 [This value should be long enough to torture the various limits of sed and 
other tools used by Autoconf.])
 
 m4_define([AT_DESCRIPTION],
-[Define to a long string if your `Autoconf' works properly.])
+[Define to a long string if your 'Autoconf' works properly.])
 
 
 # AT_DUMMY_VAR(NUMBER)
@@ -1068,7 +1068,7 @@ AT_CHECK_AUTOCONF([], [], [], [stderr])
 dnl Older versions of m4 report error at line 5 (end of macro);
 dnl newer versions report it at line 4 (start of macro).
 AT_CHECK([[sed '/trailer\.m4:/d; s/^configure\.ac:[45]: //' stderr]], [],
-[[warning: AC_DEFINE: `one
+[[warning: AC_DEFINE: 'one
 two' is not a valid preprocessor define value
 ]])
 AT_CHECK_AUTOHEADER([], [foo])
@@ -1083,7 +1083,7 @@ two], [This spans two lines.])
 ]])
 AT_CHECK_AUTOCONF([], [], [], [stderr])
 AT_CHECK([[sed '/trailer.m4:/d; s/^configure\.ac:[45]: //' stderr]], [],
-[[warning: AC_DEFINE_UNQUOTED: `one
+[[warning: AC_DEFINE_UNQUOTED: 'one
 two' is not a valid preprocessor define value
 ]])
 AT_CHECK_AUTOHEADER([], [foo])
@@ -1148,7 +1148,7 @@ d@&t@nl The following line silences the warnings, if 
uncommented:
 d@&t@nl AC_DEFUN([AC_DATAROOTDIR_CHECKED])
 
 # This substitution is wrong and bogus!  Don't use it in your own code!
-# Read `info Autoconf "Defining Directories"'!
+# Read 'info Autoconf "Defining Directories"'!
 AC_SUBST([mydatadir], [${datadir}/my])
 
 AC_CONFIG_FILES([Foo Bar])
@@ -1160,7 +1160,7 @@ cp "$abs_top_srcdir/build-aux/install-sh" .
 AT_CHECK_AUTOCONF
 AT_CHECK_CONFIGURE([], [], [],
   [config.status: WARNING:  'Foo.in' seems to ignore the --datarootdir setting
-config.status: WARNING: Bar contains a reference to the variable `datarootdir'
+config.status: WARNING: Bar contains a reference to the variable 'datarootdir'
 which seems to be undefined.  Please make sure it is defined
 ])
 AT_CHECK([grep datarootdir Foo], 1, [])
@@ -1468,7 +1468,7 @@ mkdir empty
 ACLOCAL="aclocal --system-acdir=`cd empty && pwd`"
 export ACLOCAL
 
-# The contents of `inner/', and `inner/innermost/'.
+# The contents of 'inner/', and 'inner/innermost/'.
 AS_MKDIR_P([inner/innermost])
 
 AT_DATA([inner/configure.ac],
@@ -1490,7 +1490,7 @@ top_srcdir=@top_srcdir@
 prefix=@prefix@
 ])
 
-# The contents of `.'
+# The contents of '.'
 AT_DATA([install-sh], [])
 
 # nonexistent is allowed not to exist.
@@ -1592,7 +1592,7 @@ mkdir empty
 ACLOCAL="aclocal --system-acdir=`cd empty && pwd`"
 export ACLOCAL
 
-# The contents of `.'
+# The contents of '.'
 AT_DATA([install-sh], [])
 AT_DATA([configure.ac],
 [[AC_INIT(GNU Outer, 1.0)
@@ -1604,7 +1604,7 @@ AC_CONFIG_SUBDIRS([
 AC_OUTPUT
 ]])
 
-# The contents of `inner/', and `inner/innermost/'.
+# The contents of 'inner/', and 'inner/innermost/'.
 AS_MKDIR_P([inner/innermost])
 AS_MKDIR_P([inner2])
 
@@ -1857,7 +1857,7 @@ ACLOCAL=true
 export ACLOCAL
 
 # The test group directory is not necessarily _empty_, but it does not contain
-# files meaningful to `autoreconf'.
+# files meaningful to 'autoreconf'.
 
 AT_CHECK([autoreconf -Wall -v], 1, [ignore], [ignore])
 
@@ -1892,7 +1892,7 @@ AC_OUTPUT
 ]])
 
 AT_DATA([HeeHee.am],
-[[# Humans do no worse than `GNUmakefile.am'.
+[[# Humans do no worse than 'GNUmakefile.am'.
 AUTOMAKE_OPTIONS = foreign 1.8
 ]])
 
diff --git a/tests/wrapper.as b/tests/wrapper.as
index e01bcb2c..a639861c 100644
--- a/tests/wrapper.as
+++ b/tests/wrapper.as
@@ -1,5 +1,5 @@
 AS_INIT[]dnl                                            -*- shell-script -*-
-# wrapper.as -- running `@wrap_program@' as if it were installed.
+# wrapper.as -- running '@wrap_program@' as if it were installed.
 # @configure_input@
 # Copyright (C) 2003-2004, 2007, 2009-2017, 2020-2021 Free Software
 # Foundation, Inc.
-- 
2.31.1




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