diff --git a/LEGO1/omni/include/mxtypes.h b/LEGO1/omni/include/mxtypes.h
index 9ec63222..caecb68a 100644
--- a/LEGO1/omni/include/mxtypes.h
+++ b/LEGO1/omni/include/mxtypes.h
@@ -52,6 +52,10 @@ typedef MxU8 MxBool;
 #define FALSE 0
 #endif
 
+#ifndef NULL
+#define NULL 0
+#endif
+
 #define TWOCC(a, b) (((a) << 0) | ((b) << 8))
 #define FOURCC(a, b, c, d) (((a) << 0) | ((b) << 8) | ((c) << 16) | ((d) << 24))