For gusi-based python
diff --git a/Mac/mwerks/mwfopenrf.c b/Mac/mwerks/mwfopenrf.c
index e07cf50..60ca3f8 100644
--- a/Mac/mwerks/mwfopenrf.c
+++ b/Mac/mwerks/mwfopenrf.c
@@ -4,7 +4,7 @@
 ** Jack Jansen, CWI, August 1995.
 */
 
-#ifdef __MWERKS__
+#if defined(__MWERKS__) && !defined(USE_GUSI)
 #include <stdio.h>
 #include <unix.h>
 #include <errno.h>