[PATCH 3/5] Remove ancient backward compatibility code from m4/m4.m4.

[Zack Weinberg]

We have had AC_PREREQ([2.69]) in our own configure.ac since 2021,
and before that it was AC_PREREQ([2.62]) since 2012, so backcompat
code for 2.61 is not necessary anymore.

Also add logging of the name of each candidate executable and bump the
serial number.
---
 m4/m4.m4 | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/m4/m4.m4 b/m4/m4.m4
index 66e7341f..42612162 100644
--- a/m4/m4.m4
+++ b/m4/m4.m4
@@ -1,4 +1,4 @@
-# m4.m4 serial 12
+# m4.m4 serial 13
 
 # Copyright (C) 2000, 2006-2017, 2020-2022 Free Software Foundation,
 # Inc.
@@ -41,6 +41,8 @@ AC_PATH_PROGS_FEATURE_CHECK([M4], [m4 gm4 gnum4],
       ac_snip2=change'quote(<,>)def''ine(<T>,<>)d'nl
       ac_snip2=${ac_snip2}${as_nl}def'ine(<F>,<T(<traced>)>)d'nl
       ac_snip2=${ac_snip2}${as_nl}m4'wrap(<F>)d'nl
+      AS_ECHO("$as_me:${as_lineno-$LINENO}: trying $ac_path_M4") \
+          >&AS_MESSAGE_LOG_FD
       test -z "`$ac_path_M4 -F conftest.m4f </dev/null 2>&1`" \
       && test -z "`AS_ECHO([$ac_snippet]) | $ac_path_M4 --trace=mac 2>&1`" \
       && test -f conftest.m4f \
@@ -80,12 +82,3 @@ Glibc 2.9 - 2.12 and GNU M4 1.4.11 - 1.4.15 have another 
strstr bug.])])])
     esac])
   AC_SUBST([M4_DEBUGFILE], [$ac_cv_prog_gnu_m4_debugfile])
 ])
-
-# Compatibility for bootstrapping with Autoconf 2.61.
-dnl FIXME - replace this with AC_PREREQ([2.62]) after the release.
-# AC_PATH_PROGS_FEATURE_CHECK was added the same time the slightly broken,
-# undocumented _AC_PATH_PROG_FEATURE_CHECK was deleted.
-m4_ifndef([AC_PATH_PROGS_FEATURE_CHECK],
-  [m4_define([AC_PATH_PROGS_FEATURE_CHECK],
-    [_AC_PATH_PROG_FEATURE_CHECK([$1], [$2], [$3], [$5])
-])])
-- 
2.36.1