gnulib/import/m4/stddef_h.m4

   1 dnl A placeholder for <stddef.h>, for platforms that have issues.
   2 # stddef_h.m4 serial 5
   3 dnl Copyright (C) 2009-2016 Free Software Foundation, Inc.
   4 dnl This file is free software; the Free Software Foundation
   5 dnl gives unlimited permission to copy and/or distribute it,
   6 dnl with or without modifications, as long as this notice is preserved.
   7
   8 AC_DEFUN([gl_STDDEF_H],
   9 [
  10   AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
  11   AC_REQUIRE([gt_TYPE_WCHAR_T])
  12   STDDEF_H=
  13   AC_CHECK_TYPE([max_align_t], [], [HAVE_MAX_ALIGN_T=0; STDDEF_H=stddef.h],
  14     [[#include <stddef.h>
  15     ]])
  16   if test $gt_cv_c_wchar_t = no; then
  17     HAVE_WCHAR_T=0
  18     STDDEF_H=stddef.h
  19   fi
  20   AC_CACHE_CHECK([whether NULL can be used in arbitrary expressions],
  21     [gl_cv_decl_null_works],
  22     [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stddef.h>
  23       int test[2 * (sizeof NULL == sizeof (void *)) -1];
  24 ]])],
  25       [gl_cv_decl_null_works=yes],
  26       [gl_cv_decl_null_works=no])])
  27   if test $gl_cv_decl_null_works = no; then
  28     REPLACE_NULL=1
  29     STDDEF_H=stddef.h
  30   fi
  31   AC_SUBST([STDDEF_H])
  32   AM_CONDITIONAL([GL_GENERATE_STDDEF_H], [test -n "$STDDEF_H"])
  33   if test -n "$STDDEF_H"; then
  34     gl_NEXT_HEADERS([stddef.h])
  35   fi
  36 ])
  37
  38 AC_DEFUN([gl_STDDEF_MODULE_INDICATOR],
  39 [
  40   dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
  41   AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
  42   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
  43 ])
  44
  45 AC_DEFUN([gl_STDDEF_H_DEFAULTS],
  46 [
  47   dnl Assume proper GNU behavior unless another module says otherwise.
  48   REPLACE_NULL=0;                AC_SUBST([REPLACE_NULL])
  49   HAVE_MAX_ALIGN_T=1;            AC_SUBST([HAVE_MAX_ALIGN_T])
  50   HAVE_WCHAR_T=1;                AC_SUBST([HAVE_WCHAR_T])
  51 ])