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emacs/m4/stddef_h.m4

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dnl A placeholder for POSIX 2008 <stddef.h>, for platforms that have issues.
# stddef_h.m4 serial 4
dnl Copyright (C) 2009-2011 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_STDDEF_H],
[
AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
AC_REQUIRE([gt_TYPE_WCHAR_T])
STDDEF_H=
if test $gt_cv_c_wchar_t = no; then
HAVE_WCHAR_T=0
STDDEF_H=stddef.h
fi
AC_CACHE_CHECK([whether NULL can be used in arbitrary expressions],
[gl_cv_decl_null_works],
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stddef.h>
int test[2 * (sizeof NULL == sizeof (void *)) -1];
]])],
[gl_cv_decl_null_works=yes],
[gl_cv_decl_null_works=no])])
if test $gl_cv_decl_null_works = no; then
REPLACE_NULL=1
STDDEF_H=stddef.h
fi
AC_SUBST([STDDEF_H])
AM_CONDITIONAL([GL_GENERATE_STDDEF_H], [test -n "$STDDEF_H"])
if test -n "$STDDEF_H"; then
gl_NEXT_HEADERS([stddef.h])
fi
])
AC_DEFUN([gl_STDDEF_MODULE_INDICATOR],
[
dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
gl_MODULE_INDICATOR_SET_VARIABLE([$1])
])
AC_DEFUN([gl_STDDEF_H_DEFAULTS],
[
dnl Assume proper GNU behavior unless another module says otherwise.
REPLACE_NULL=0; AC_SUBST([REPLACE_NULL])
HAVE_WCHAR_T=1; AC_SUBST([HAVE_WCHAR_T])
])