Clean up @var handling in the manual.

[Ralf Wildenhues]

Similarly to a recent patch for Libtool, this cleans up the Automake
manual use of @var.  IMHO, the lower-casing really helps the PDF
rendering, making metasyntactic variables much easier to detect.

Tested make info pdf html, glossed over, committed to maint.

Cheers,
Ralf

    Clean up @var handling in the manual.
    
    * doc/automake.texi: Throughout the manual, lower-case @var
    names, replace a few one-character names.

diff --git a/doc/automake.texi b/doc/automake.texi
index 641643b..48f0ab4 100644
--- a/doc/automake.texi
+++ b/doc/automake.texi
@@ -1017,11 +1017,11 @@ resulting executable is expected to run.  The following
 @command{configure} options are used to specify each of them:
 
 @table @option
address@hidden address@hidden
address@hidden address@hidden
address@hidden address@hidden
address@hidden address@hidden
 The system on which the package is built.
address@hidden address@hidden
address@hidden address@hidden
address@hidden address@hidden
address@hidden address@hidden
 The system where built programs and libraries will run.
 @end table
 
@@ -1067,15 +1067,15 @@ built is itself a cross-compiler: we need a third 
option to specify
 its target architecture.
 
 @table @option
address@hidden address@hidden
address@hidden address@hidden
address@hidden address@hidden
address@hidden address@hidden
 When building compiler tools: the system for which the tools will
 create output.
 @end table
 
 For instance when installing GCC, the GNU Compiler Collection, we can
-use @option{--target=@/@var{TARGET}} to specify that we want to build
-GCC as a cross-compiler for @var{TARGET}.  Mixing @option{--build} and
+use @option{--target=@/@var{target}} to specify that we want to build
+GCC as a cross-compiler for @var{target}.  Mixing @option{--build} and
 @option{--target}, we can actually cross-compile a cross-compiler;
 such a three-way cross-compilation is known as a @dfn{Canadian cross}.
 
@@ -1100,15 +1100,15 @@ distinguish it from your vendor's @command{tar}.
 This can be done using one of these three @command{configure} options.
 
 @table @option
address@hidden address@hidden
address@hidden address@hidden
-Prepend @var{PREFIX} to installed program names.
address@hidden address@hidden
address@hidden address@hidden
-Append @var{SUFFIX} to installed program names.
address@hidden address@hidden
address@hidden address@hidden
-Run @code{sed @var{PROGRAM}} on installed program names.
address@hidden address@hidden
address@hidden address@hidden
+Prepend @var{prefix} to installed program names.
address@hidden address@hidden
address@hidden address@hidden
+Append @var{suffix} to installed program names.
address@hidden address@hidden
address@hidden address@hidden
+Run @code{sed @var{program}} on installed program names.
 @end table
 
 The following commands would install @file{hello}
@@ -3137,7 +3137,7 @@ output file.
 
 @cindex serial number and @option{--install}
 When this option is used, and only when this option is used,
address@hidden will also honor @samp{#serial @var{NUMBER}} lines
address@hidden will also honor @samp{#serial @var{number}} lines
 that appear in macros: an M4 file is ignored if there exists another
 M4 file with the same basename and a greater serial number in the
 search path (@pxref{Serials}).
@@ -3532,11 +3532,11 @@ automatically when new system-wide versions are 
installed.  A serial
 number should be a single line of the form
 
 @example
-#serial @var{NNN}
+#serial @var{nnn}
 @end example
 
 @noindent
-where @var{NNN} contains only digits and dots.  It should appear in
+where @var{nnn} contains only digits and dots.  It should appear in
 the M4 file before any macro definition.  It is a good practice to
 maintain a serial number for each macro you distribute, even if you do
 not use the @option{--install} option of @command{aclocal}: this allows
@@ -5314,7 +5314,7 @@ options and generic options.  Mode-specific options such 
as the
 aforementioned linking flags should be lumped with the other flags
 passed to the tool invoked by @command{libtool} (hence the use of
 @address@hidden for libtool linking flags).  Generic
-options include @address@hidden and @option{--silent}
+options include @address@hidden and @option{--silent}
 (@pxref{Invoking libtool, , Invoking @command{libtool}, libtool, The
 Libtool Manual} for more options) should appear before the mode
 selection on the command line; in @file{Makefile.am}s they should
@@ -5323,10 +5323,10 @@ be listed in the @address@hidden variable.
 If @address@hidden is not defined, then the variable
 @code{AM_LIBTOOLFLAGS} is used instead.
 
-These flags are passed to libtool after the @address@hidden
+These flags are passed to libtool after the @address@hidden
 option computed by Automake (if any), so
 @address@hidden (or @code{AM_LIBTOOLFLAGS}) is a
-good place to override or supplement the @address@hidden
+good place to override or supplement the @address@hidden
 setting.
 
 The libtool rules also use a @code{LIBTOOLFLAGS} variable that should
@@ -5573,7 +5573,7 @@ or a shared library.  It overrides the @code{AM_LDFLAGS} 
variable.
 @item maude_LIBTOOLFLAGS
 This variable is used to pass extra options to @command{libtool}.
 It overrides the @code{AM_LIBTOOLFLAGS} variable.
-These options are output before @command{libtool}'s @address@hidden
+These options are output before @command{libtool}'s @address@hidden
 option, so they should not be mode-specific options (those belong to
 the compiler or linker flags).  @xref{Libtool Flags}.
 
@@ -5755,8 +5755,8 @@ Without the last line, they will be built from 
@file{test1.c},
 @cindex Libtool modules, default source example
 @cindex default source, Libtool modules example
 Another case where this is convenient is building many Libtool modules
-(@address@hidden), each defined in its own file
-(@address@hidden).
+(@address@hidden), each defined in its own file
+(@address@hidden).
 
 @example
 AM_LDFLAGS = -module
@@ -6556,8 +6556,8 @@ library.
 @comment  node-name,  next,  previous,  up
 @subsection Compiling Fortran 9x Files
 
address@hidden@var{N}.o} is made automatically from @address@hidden,
address@hidden@var{N}.f95}, @address@hidden, or @address@hidden
address@hidden@var{file}.o} is made automatically from @address@hidden,
address@hidden@var{file}.f95}, @address@hidden, or @address@hidden
 by running the Fortran 9x compiler.  The precise command used
 is as follows:
 
@@ -6639,7 +6639,7 @@ Automake ships with an Autoconf macro called 
@code{AM_PROG_VALAC}
 that will locate the Vala compiler and optionally check its version
 number.
 
address@hidden AM_PROG_VALAC (@ovar{MINIMUM-VERSION})
address@hidden AM_PROG_VALAC (@ovar{minimum-version})
 Try to find a Vala compiler in @env{PATH}. If it is found, the variable
 @code{VALAC} is set. Optionally a minimum release number of the compiler
 can be requested:
@@ -7537,17 +7537,17 @@ files in your @file{Makefile.am}, depending on where 
you want your files
 installed (see the definitions of @code{pythondir} and
 @code{pkgpythondir} below).
 
address@hidden AM_PATH_PYTHON (@ovar{VERSION}, @ovar{ACTION-IF-FOUND}, 
@ovar{ACTION-IF-NOT-FOUND})
address@hidden AM_PATH_PYTHON (@ovar{version}, @ovar{action-if-found}, 
@ovar{action-if-not-found})
 
 Search for a Python interpreter on the system.  This macro takes three
 optional arguments.  The first argument, if present, is the minimum
 version of Python required for this package: @code{AM_PATH_PYTHON}
-will skip any Python interpreter that is older than @var{VERSION}.
-If an interpreter is found and satisfies @var{VERSION}, then
address@hidden is run.  Otherwise, @var{ACTION-IF-NOT-FOUND} is
+will skip any Python interpreter that is older than @var{version}.
+If an interpreter is found and satisfies @var{version}, then
address@hidden is run.  Otherwise, @var{action-if-not-found} is
 run.
 
-If @var{ACTION-IF-NOT-FOUND} is not specified, as in the following
+If @var{action-if-not-found} is not specified, as in the following
 example, the default is to abort @command{configure}.
 
 @example
@@ -7572,7 +7572,7 @@ the Python installation found during configuration.
 The name of the Python executable, or @samp{:} if no suitable
 interpreter could be found.
 
-Assuming @var{ACTION-IF-NOT-FOUND} is used (otherwise @file{./configure}
+Assuming @var{action-if-not-found} is used (otherwise @file{./configure}
 will abort if Python is absent), the value of @code{PYTHON} can be used
 to setup a conditional in order to disable the relevant part of a build
 as follows.
@@ -7873,8 +7873,8 @@ subdirectory of @code{mandir}.  Valid section names are 
the digits
 Sometimes developers prefer to name a man page something like
 @file{foo.man} in the source, and then rename it to have the correct
 suffix, for example @file{foo.1}, when installing the file.  Automake
-also supports this mode.  For a valid section named @var{SECTION},
-there is a corresponding directory named @address@hidden,
+also supports this mode.  For a valid section named @var{section},
+there is a corresponding directory named @address@hidden,
 and a corresponding @code{_MANS} variable.  Files listed in such a
 variable are installed in the indicated section.  If the file already
 has a valid suffix, then it is installed as-is; otherwise the file
@@ -7904,7 +7904,7 @@ installed by default.  The user can still explicitly 
install them via
 @samp{make install-man}.
 
 For fast installation, with many files it is preferable to use
address@hidden@var{SECTION}_MANS} over @samp{man_MANS} as well as files that
address@hidden@var{section}_MANS} over @samp{man_MANS} as well as files that
 do not need to be renamed.
 
 Man pages are not currently considered to be source, because it is not
@@ -8613,10 +8613,10 @@ if a test file name ends in several concatenated 
suffixes.
 @vindex LOG_COMPILE
 @vindex LOG_COMPILER
 @vindex LOG_FLAGS
address@hidden @var{EXT}_LOG_COMPILE
address@hidden @var{EXT}_LOG_COMPILER
address@hidden @var{EXT}_LOG_FLAGS
address@hidden address@hidden
address@hidden @var{ext}_LOG_COMPILE
address@hidden @var{ext}_LOG_COMPILER
address@hidden @var{ext}_LOG_FLAGS
address@hidden address@hidden
 @vindex AM_LOG_FLAGS
 For tests that match an extension @address@hidden listed in
 @code{TEST_EXTENSIONS}, you can provide a test driver using the variable
@@ -9120,10 +9120,10 @@ Enable test suite driver for @code{TESTS} that can run 
tests in parallel
 If this release is an alpha release, and the file @file{README-alpha}
 exists, then it will be added to the distribution.  If this option is
 given, version numbers are expected to follow one of two forms.  The
-first form is @address@hidden@address@hidden, where each
+first form is @address@hidden@address@hidden, where each
 element is a number; the final period and number should be left off for
 non-alpha releases.  The second form is
address@hidden@address@hidden@var{ALPHA}}, where @var{ALPHA} is a
address@hidden@address@hidden@var{alpha}}, where @var{alpha} is a
 letter; it should be omitted for non-alpha releases.
 
 @item @option{silent-rules}