diff --git a/git-compat-util.h b/git-compat-util.h
index 044f87454a..ca7678a379 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -403,6 +403,7 @@ char *gitdirname(char *);
 
 #ifndef NO_OPENSSL
 #ifdef __APPLE__
+#undef __AVAILABILITY_MACROS_USES_AVAILABILITY
 #define __AVAILABILITY_MACROS_USES_AVAILABILITY 0
 #include <AvailabilityMacros.h>
 #undef DEPRECATED_ATTRIBUTE