diff --git a/git-compat-util.h b/git-compat-util.h
index bc296b3a45..41fa7f67bc 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -11,8 +11,10 @@
 
 #define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
 
+#ifndef __APPLE_CC__
 #define _XOPEN_SOURCE 600 /* glibc2 and AIX 5.3L need 500, OpenBSD needs 600 for S_ISLNK() */
 #define _XOPEN_SOURCE_EXTENDED 1 /* AIX 5.3L needs this */
+#endif
 #define _GNU_SOURCE
 #define _BSD_SOURCE