diff --git a/src/Fl_Sys_Menu_Bar.mm b/src/Fl_Sys_Menu_Bar.mm
index c239924ad..30dfe5feb 100644
--- a/src/Fl_Sys_Menu_Bar.mm
+++ b/src/Fl_Sys_Menu_Bar.mm
@@ -43,6 +43,16 @@
 
 #import <Cocoa/Cocoa.h>
 
+#ifndef NSINTEGER_DEFINED // appears with 10.5 in NSObjCRuntime.h
+#if defined(__LP64__) && __LP64__
+typedef long NSInteger;
+typedef unsigned long NSUInteger;
+#else
+typedef long NSInteger;
+typedef unsigned int NSUInteger;
+#endif
+#endif
+
 #include "flstring.h"
 #include <stdio.h>
 #include <ctype.h>