diff --git a/src/os_mac.h b/src/os_mac.h
index 78b79c2e16..9546b6d36e 100644
--- a/src/os_mac.h
+++ b/src/os_mac.h
@@ -16,6 +16,11 @@
 # define OPAQUE_TOOLBOX_STRUCTS 0
 #endif
 
+/* Include MAC_OS_X_VERSION_* macros (needed for OS X 10.9, should be supported
+ * as of OS X 10.2)
+ * */
+#include <AvailabilityMacros.h>
+
 /*
  * Macintosh machine-dependent things.
  *