Fixed compilation on Mac OS X 10.3.9

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%403511

src/haptic/darwin/SDL_syshaptic.c

@@ -35,6 +35,9 @@
 #include <ForceFeedback/ForceFeedback.h>
 #include <ForceFeedback/ForceFeedbackConstants.h>
 
+#ifndef IO_OBJECT_NULL
+#define IO_OBJECT_NULL	((io_service_t)0)
+#endif
 
 #define MAX_HAPTICS  32