config/override.m4

   1 dnl Fix Autoconf bugs by overriding broken internal Autoconf
   2 dnl macros with backports of fixes from newer releases.
   3 dnl
   4 dnl The override bits of this file should be a no-op for the newest
   5 dnl Autoconf version, which means they can be removed once the complete
   6 dnl tree has moved to a new enough Autoconf version.
   7 dnl
   8 dnl The _GCC_AUTOCONF_VERSION_TEST ensures that exactly the desired
   9 dnl Autoconf version is used.  It should be kept for consistency.
  10
  11 dnl Use ifdef/ifelse over m4_ifdef/m4_ifelse to be clean for 2.13.
  12 ifdef([m4_PACKAGE_VERSION], [
  13
  14 dnl Provide m4_copy_force and m4_rename_force for old Autoconf versions.
  15
  16 m4_ifndef([m4_copy_force],
  17 [m4_define([m4_copy_force],
  18 [m4_ifdef([$2], [m4_undefine([$2])])m4_copy($@)])])
  19
  20 m4_ifndef([m4_rename_force],
  21 [m4_define([m4_rename_force],
  22 [m4_ifdef([$2], [m4_undefine([$2])])m4_rename($@)])])
  23
  24 dnl AC_DEFUN a commonly used macro so this file is picked up.
  25 m4_copy([AC_PREREQ], [_AC_PREREQ])
  26 AC_DEFUN([AC_PREREQ], [frob])
  27 m4_copy_force([_AC_PREREQ], [AC_PREREQ])
  28
  29
  30 dnl Ensure exactly this Autoconf version is used
  31 m4_ifndef([_GCC_AUTOCONF_VERSION],
  32   [m4_define([_GCC_AUTOCONF_VERSION], [2.69])])
  33
  34 dnl Test for the exact version when AC_INIT is expanded.
  35 dnl This allows to update the tree in steps (for testing)
  36 dnl by putting
  37 dnl   m4_define([_GCC_AUTOCONF_VERSION], [X.Y])
  38 dnl in configure.ac before AC_INIT,
  39 dnl without rewriting this file.
  40 dnl Or for updating the whole tree at once with the definition above.
  41 AC_DEFUN([_GCC_AUTOCONF_VERSION_CHECK],
  42 [m4_if(m4_defn([_GCC_AUTOCONF_VERSION]),
  43   m4_defn([m4_PACKAGE_VERSION]), [],
  44   [m4_fatal([Please use exactly Autoconf ]_GCC_AUTOCONF_VERSION[ instead of ]m4_defn([m4_PACKAGE_VERSION])[.])])
  45 ])
  46 m4_define([AC_INIT], m4_defn([AC_INIT])[
  47 _GCC_AUTOCONF_VERSION_CHECK
  48 ])
  49
  50
  51 dnl Ensure we do not use a buggy M4.
  52 m4_if(m4_index([..wi.d.], [.d.]), [-1],
  53   [m4_fatal(m4_do([m4 with buggy strstr detected.  Please install
  54 GNU M4 1.4.16 or newer and set the M4 environment variable]))])
  55
  56
  57 dnl Fix 2.64 cross compile detection for AVR and RTEMS
  58 dnl by not trying to compile fopen.
  59 m4_if(m4_defn([m4_PACKAGE_VERSION]), [2.64],
  60   [m4_foreach([_GCC_LANG], [C, C++, Fortran, Fortran 77],
  61      [m4_define([_AC_LANG_IO_PROGRAM(]_GCC_LANG[)], m4_defn([AC_LANG_PROGRAM(]_GCC_LANG[)]))])])
  62
  63 m4_version_prereq([2.66],, [
  64 dnl We need AC_CHECK_DECL which works for overloaded C++ functions.
  65
  66 # _AC_CHECK_DECL_BODY
  67 # -------------------
  68 # Shell function body for AC_CHECK_DECL.
  69 m4_define([_AC_CHECK_DECL_BODY],
  70 [  AS_LINENO_PUSH([$[]1])
  71   [as_decl_name=`echo $][2|sed 's/ *(.*//'`]
  72   [as_decl_use=`echo $][2|sed -e 's/(/((/' -e 's/)/) 0&/' -e 's/,/) 0& (/g'`]
  73   AC_CACHE_CHECK([whether $as_decl_name is declared], [$[]3],
  74   [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([$[]4],
  75 [@%:@ifndef $[]as_decl_name
  76 @%:@ifdef __cplusplus
  77   (void) $[]as_decl_use;
  78 @%:@else
  79   (void) $[]as_decl_name;
  80 @%:@endif
  81 @%:@endif
  82 ])],
  83                    [AS_VAR_SET([$[]3], [yes])],
  84                    [AS_VAR_SET([$[]3], [no])])])
  85   AS_LINENO_POP
  86 ])# _AC_CHECK_DECL_BODY
  87
  88 # _AC_CHECK_DECLS(SYMBOL, ACTION-IF_FOUND, ACTION-IF-NOT-FOUND,
  89 #                 INCLUDES)
  90 # -------------------------------------------------------------
  91 # Helper to AC_CHECK_DECLS, which generates the check for a single
  92 # SYMBOL with INCLUDES, performs the AC_DEFINE, then expands
  93 # ACTION-IF-FOUND or ACTION-IF-NOT-FOUND.
  94 m4_define([_AC_CHECK_DECLS],
  95 [AC_CHECK_DECL([$1], [ac_have_decl=1], [ac_have_decl=0], [$4])]dnl
  96 [AC_DEFINE_UNQUOTED(AS_TR_CPP(m4_bpatsubst(HAVE_DECL_[$1],[ *(.*])),
  97   [$ac_have_decl],
  98   [Define to 1 if you have the declaration of `$1',
  99    and to 0 if you don't.])]dnl
 100 [m4_ifvaln([$2$3], [AS_IF([test $ac_have_decl = 1], [$2], [$3])])])
 101
 102 ])
 103
 104 dnl If flex/lex are not found, the top level configure sets LEX to
 105 dnl "/path_to/missing flex".  When AC_PROG_LEX tries to find the flex
 106 dnl output file, it calls $LEX to do so, but the current lightweight
 107 dnl "missing" won't create a file.  This results in an error.
 108 dnl Avoid calling the bulk of AC_PROG_LEX when $LEX is "missing".
 109 AC_DEFUN_ONCE([AC_PROG_LEX],
 110 [AC_CHECK_PROGS(LEX, flex lex, :)
 111 case "$LEX" in
 112   :|*"missing "*) ;;
 113   *) _AC_PROG_LEX_YYTEXT_DECL ;;
 114 esac])
 115
 116 ])