3 # Copyright (C) 2000, 2006-2016 Free Software Foundation, Inc.
5 # Copying and distribution of this file, with or without modification,
6 # are permitted in any medium without royalty provided the copyright
7 # notice and this notice are preserved. This file is offered as-is,
8 # without warranty of any kind.
12 # Check for GNU M4, at least 1.4.6 (all earlier versions had bugs in
13 # trace support and regexp support):
14 # http://lists.gnu.org/archive/html/bug-gnu-utils/2006-11/msg00096.html
15 # http://lists.gnu.org/archive/html/bug-autoconf/2009-07/msg00023.html
16 # Also, check whether --error-output (through 1.4.x) or --debugfile (2.0)
17 # is supported, and AC_SUBST M4_DEBUGFILE accordingly.
18 # Also avoid versions of m4 that trigger strstr bugs.
19 AC_DEFUN([AC_PROG_GNU_M4],
20 [AC_ARG_VAR([M4], [Location of GNU M4 1.4.6 or later. Defaults to the first
21 program of 'm4', 'gm4', or 'gnum4' on PATH that meets Autoconf needs.])
22 AC_CACHE_CHECK([for GNU M4 that supports accurate traces], [ac_cv_path_M4],
24 ac_had_posixly_correct=${POSIXLY_CORRECT:+yes}
25 AS_UNSET([POSIXLY_CORRECT])
26 AC_PATH_PROGS_FEATURE_CHECK([M4], [m4 gm4 gnum4],
27 [dnl Creative quoting here to avoid raw dnl and ifdef in configure.
28 # Root out GNU M4 1.4.5, as well as non-GNU m4 that ignore -t, -F.
29 # Root out GNU M4 1.4.15 with buggy false negative replacement strstr.
30 # Root out Glibc 2.9 - 2.12 and GNU M4 1.4.11 - 1.4.15 with buggy
31 # false positive strstr.
32 ac_snippet=change'quote(<,>)in''dir(<if''def>,mac,bug)'
33 ac_snippet=${ac_snippet}pat'subst(a,\(b\)\|\(a\),\1)d'nl
34 ac_snippet=${ac_snippet}${as_nl}if'else(in''dex(..wi.d.,.d.),-1,bug)'
35 ac_snippet=${ac_snippet}${as_nl}if'else(in''dex(dnl
36 ;:11-:12-:12-:12-:12-:12-:12-:12-:12.:12.:12.:12.:12.:12.:12.:12.:12-,dnl
37 :12-:12-:12-:12-:12-:12-:12-:12-),-1,,strstr-bug2)'
38 test -z "`$ac_path_M4 -F conftest.m4f </dev/null 2>&1`" \
39 && test -z "`AS_ECHO([$ac_snippet]) | $ac_path_M4 --trace=mac 2>&1`" \
40 && test -f conftest.m4f \
41 && ac_cv_path_M4=$ac_path_M4 ac_path_M4_found=:
43 [AC_MSG_ERROR([no acceptable m4 could be found in \$PATH.
44 GNU M4 1.4.6 or later is required; 1.4.16 or newer is recommended.
45 GNU M4 1.4.15 uses a buggy replacement strstr on some systems.
46 Glibc 2.9 - 2.12 and GNU M4 1.4.11 - 1.4.15 have another strstr bug.])])])
48 AC_CACHE_CHECK([whether $ac_cv_path_M4 accepts --gnu],
49 [ac_cv_prog_gnu_m4_gnu],
50 [case `$M4 --help < /dev/null 2>&1` in
51 *--gnu*) ac_cv_prog_gnu_m4_gnu=yes ;;
52 *) ac_cv_prog_gnu_m4_gnu=no ;;
54 if test "$ac_cv_prog_gnu_m4_gnu" = yes; then
60 if test x$ac_had_posixly_correct = xyes; then
62 if test $ac_cv_prog_gnu_m4_gnu = no; then
63 AC_MSG_WARN([the version of M4 that was found does not support -g])
64 AC_MSG_WARN([using it with POSIXLY_CORRECT set may cause problems])
67 AC_CACHE_CHECK([how m4 supports trace files], [ac_cv_prog_gnu_m4_debugfile],
68 [case `$M4 --help < /dev/null 2>&1` in
69 *debugfile*) ac_cv_prog_gnu_m4_debugfile=--debugfile ;;
70 *) ac_cv_prog_gnu_m4_debugfile=--error-output ;;
72 AC_SUBST([M4_DEBUGFILE], [$ac_cv_prog_gnu_m4_debugfile])
75 # Compatibility for bootstrapping with Autoconf 2.61.
76 dnl FIXME - replace this with AC_PREREQ([2.62]) after the release.
77 # AC_PATH_PROGS_FEATURE_CHECK was added the same time the slightly broken,
78 # undocumented _AC_PATH_PROG_FEATURE_CHECK was deleted.
79 m4_ifndef([AC_PATH_PROGS_FEATURE_CHECK],
80 [m4_define([AC_PATH_PROGS_FEATURE_CHECK],
81 [_AC_PATH_PROG_FEATURE_CHECK([$1], [$2], [$3], [$5])