stddef: fix NetBSD 5.0 NULL bug, rather than working around it

[gnulib.git] / m4 / getdate.m4

diff --git a/m4/getdate.m4 b/m4/getdate.m4
index 978cf50..67f9c65 100644 (file)
--- a/m4/getdate.m4
+++ b/m4/getdate.m4
@@ -1,9 +1,29 @@
-# getdate.m4 serial 6
-dnl Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
+# getdate.m4 serial 14
+dnl Copyright (C) 2002-2006, 2008, 2009 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.
 
+dnl Define HAVE_COMPOUND_LITERALS if the C compiler supports compound literals
+dnl as in ISO C99.
+dnl Note that compound literals such as (struct s) { 3, 4 } can be used for
+dnl initialization of stack-allocated variables, but are not constant
+dnl expressions and therefore cannot be used as initializer for global or
+dnl static variables (even though gcc supports this in pre-C99 mode).
+AC_DEFUN([gl_C_COMPOUND_LITERALS],
+[
+  AC_CACHE_CHECK([for compound literals], [gl_cv_compound_literals],
+  [AC_TRY_COMPILE([struct s { int i, j; };],
+    [struct s t = (struct s) { 3, 4 };
+     if (t.i != 0) return 0;],
+    gl_cv_compound_literals=yes,
+    gl_cv_compound_literals=no)])
+  if test $gl_cv_compound_literals = yes; then
+    AC_DEFINE([HAVE_COMPOUND_LITERALS], [1],
+      [Define if you have compound literals.])
+  fi
+])
+
 AC_DEFUN([gl_GETDATE],
 [
   dnl Prerequisites of lib/getdate.h.
@@ -12,8 +32,7 @@ AC_DEFUN([gl_GETDATE],
 
   dnl Prerequisites of lib/getdate.y.
   AC_REQUIRE([gl_BISON])
-  AC_REQUIRE([AC_HEADER_STDC])
-  AC_CHECK_FUNCS_ONCE(isascii)
+  AC_REQUIRE([gl_C_COMPOUND_LITERALS])
   AC_STRUCT_TIMEZONE
   AC_REQUIRE([gl_CLOCK_TIME])
   AC_REQUIRE([gl_TM_GMTOFF])