m4/stddef_h.m4

   1 dnl A placeholder for POSIX 2008 <stddef.h>, for platforms that have issues.
   2 # stddef_h.m4 serial 4
   3 dnl Copyright (C) 2009-2014 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   if test $gt_cv_c_wchar_t = no; then
  14     HAVE_WCHAR_T=0
  15     STDDEF_H=stddef.h
  16   fi
  17   AC_CACHE_CHECK([whether NULL can be used in arbitrary expressions],
  18     [gl_cv_decl_null_works],
  19     [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stddef.h>
  20       int test[2 * (sizeof NULL == sizeof (void *)) -1];
  21 ]])],
  22       [gl_cv_decl_null_works=yes],
  23       [gl_cv_decl_null_works=no])])
  24   if test $gl_cv_decl_null_works = no; then
  25     REPLACE_NULL=1
  26     STDDEF_H=stddef.h
  27   fi
  28   AC_SUBST([STDDEF_H])
  29   AM_CONDITIONAL([GL_GENERATE_STDDEF_H], [test -n "$STDDEF_H"])
  30   if test -n "$STDDEF_H"; then
  31     gl_NEXT_HEADERS([stddef.h])
  32   fi
  33 ])
  34
  35 AC_DEFUN([gl_STDDEF_MODULE_INDICATOR],
  36 [
  37   dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
  38   AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
  39   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
  40 ])
  41
  42 AC_DEFUN([gl_STDDEF_H_DEFAULTS],
  43 [
  44   dnl Assume proper GNU behavior unless another module says otherwise.
  45   REPLACE_NULL=0;                AC_SUBST([REPLACE_NULL])
  46   HAVE_WCHAR_T=1;                AC_SUBST([HAVE_WCHAR_T])
  47 ])