--- Source/WTF/wtf/Platform.h.orig	2012-10-17 21:57:04.000000000 -0700
+++ Source/WTF/wtf/Platform.h	2012-10-17 21:57:40.000000000 -0700
@@ -321,8 +321,10 @@
 #ifdef __APPLE__
 #define WTF_OS_DARWIN 1
 
-#include <Availability.h>
 #include <AvailabilityMacros.h>
+#if MAC_OS_X_VERSION_MAX_ALLOWED >= 1050
+#include <Availability.h>
+#endif
 #include <TargetConditionals.h>
 #endif