libintl.h warnings with -Wundef

[Christian Weisgerber]

Projects that include libintl.h and build with gcc -Wundef show warnings
such as these:

/usr/local/include/libintl.h:91:25: warning: "__APPLE_CC__" is not defined
/usr/local/include/libintl.h:113:24: warning: "__APPLE_CC__" is not defined

Non-GCC compilers may show a similar warning for __GNUC__.

Check that macros are defined before testing their value:

--- gettext-runtime/intl/libgnuintl.h.in.orig   Thu Sep 18 16:19:59 2008
+++ gettext-runtime/intl/libgnuintl.h.in        Thu Sep 18 16:28:56 2008
@@ -88,7 +88,7 @@ extern int libintl_version;
    If he doesn't, we choose the method.  A third possible method is
    _INTL_REDIRECT_ASM, supported only by GCC.  */
 #if !(defined _INTL_REDIRECT_INLINE || defined _INTL_REDIRECT_MACROS)
-# if __GNUC__ >= 2 && !(__APPLE_CC__ > 1) && !defined __MINGW32__ && 
!(__GNUC__ == 2 && defined _AIX) && (defined __STDC__ || defined __cplusplus)
+# if (defined __GNUC__ && __GNUC__ >= 2) && !(defined __APPLE_CC_ && 
__APPLE_CC__ > 1) && !defined __MINGW32__ && !(__GNUC__ == 2 && defined _AIX) 
&& (defined __STDC__ || defined __cplusplus)
 #  define _INTL_REDIRECT_ASM
 # else
 #  ifdef __cplusplus
@@ -110,7 +110,7 @@ extern int libintl_version;
 /* _INTL_MAY_RETURN_STRING_ARG(n) declares that the given function may return
    its n-th argument literally.  This enables GCC to warn for example about
    printf (gettext ("foo %y")).  */
-#if __GNUC__ >= 3 && !(__APPLE_CC__ > 1 && defined __cplusplus)
+#if (defined __GNUC__ && __GNUC__ >= 3) && !(defined __APPLE_CC__ && 
__APPLE_CC__ > 1 && defined __cplusplus)
 # define _INTL_MAY_RETURN_STRING_ARG(n) __attribute__ ((__format_arg__ (n)))
 #else
 # define _INTL_MAY_RETURN_STRING_ARG(n)
-- 
Christian "naddy" Weisgerber                          address@hidden