diff --git a/Source/behavior.m b/Source/behavior.m
index f3c5c50d1..f6ec77586 100644
--- a/Source/behavior.m
+++ b/Source/behavior.m
@@ -55,10 +55,12 @@
 #include <Foundation/NSException.h>
 
 /* Darwin behavior */
+#if NeXT_RUNTIME
 #if !defined(Release3CompatibilityBuild)
 #define methods methodLists
 #define method_next obsolete
 #endif
+#endif
 
 static struct objc_method *search_for_method_in_list (struct objc_method_list * list, SEL op);
 static BOOL class_is_kind_of(Class self, Class class);