Made format_arg attribute require clang (apparently it doesn't work with GCC, in spite of being listed in the GCC manual - possibly it only works with C functions). If it works with GCC 4.6, the #ifdef should be changed.

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@31808 72102866-910b-0410-8b05-ffd578937521

Headers/Foundation/NSBundle.h

@@ -304,7 +304,11 @@ GS_EXPORT NSString* const NSLoadedClasses;
  */
 - (NSString*) localizedStringForKey: (NSString*)key
 			      value: (NSString*)value
-			      table: (NSString*)tableName __attribute__((format_arg(1)));
+			      table: (NSString*)tableName 
+#ifdef __clang__
+				  __attribute__((format_arg(1)))
+#endif
+	;
 
 /** Returns the absolute path to the resources directory of the bundle.  */
 - (NSString*) resourcePath;