1# m4.m4 serial 12
2
3# Copyright (C) 2000, 2006-2012 Free Software Foundation, Inc.
4
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.
9
10# AC_PROG_GNU_M4
11# --------------
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.
19AC_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],
23    [rm -f conftest.m4f
24ac_had_posixly_correct=${POSIXLY_CORRECT:+yes}
25AS_UNSET([POSIXLY_CORRECT])
26AC_PATH_PROGS_FEATURE_CHECK([M4], [m4 gm4 gnum4],
27      [dnl Creative quoting here to avoid raw dnl and ifdef in configure.
28      # Root out GNU M4 1.4.5, as well as non-GNU m4 that ignore -t, -F.
29      # Root out GNU M4 1.4.15 with buggy false negative replacement strstr.
30      # Root out Glibc 2.9 - 2.12 and GNU M4 1.4.11 - 1.4.15 with buggy
31      # false positive strstr.
32      ac_snippet=change'quote(<,>)in''dir(<if''def>,mac,bug)'
33      ac_snippet=${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=:
42      rm -f conftest.m4f],
43      [AC_MSG_ERROR([no acceptable m4 could be found in \$PATH.
44GNU M4 1.4.6 or later is required; 1.4.16 or newer is recommended.
45GNU M4 1.4.15 uses a buggy replacement strstr on some systems.
46Glibc 2.9 - 2.12 and GNU M4 1.4.11 - 1.4.15 have another strstr bug.])])])
47  M4=$ac_cv_path_M4
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 ;;
53    esac])
54  if test "$ac_cv_prog_gnu_m4_gnu" = yes; then
55    M4_GNU=--gnu
56  else
57    M4_GNU=
58  fi
59  AC_SUBST([M4_GNU])
60  if test x$ac_had_posixly_correct = xyes; then
61    POSIXLY_CORRECT=:
62    if test $ac_cv_prog_gnu_m4_gnu = no; then
63      AC_MSG_WARN([the version of M4 that was found does not support -g])
64      AC_MSG_WARN([using it with POSIXLY_CORRECT set may cause problems])
65    fi
66  fi
67  AC_CACHE_CHECK([how m4 supports trace files], [ac_cv_prog_gnu_m4_debugfile],
68    [case `$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 ;;
71    esac])
72  AC_SUBST([M4_DEBUGFILE], [$ac_cv_prog_gnu_m4_debugfile])
73])
74
75# Compatibility for bootstrapping with Autoconf 2.61.
76dnl 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.
79m4_ifndef([AC_PATH_PROGS_FEATURE_CHECK],
80  [m4_define([AC_PATH_PROGS_FEATURE_CHECK],
81    [_AC_PATH_PROG_FEATURE_CHECK([$1], [$2], [$3], [$5])
82])])
83