diff --git a/stepmania/src/archutils/Darwin/arch_setup.h b/stepmania/src/archutils/Darwin/arch_setup.h
index e27abe9eb3..bd90dded01 100644
--- a/stepmania/src/archutils/Darwin/arch_setup.h
+++ b/stepmania/src/archutils/Darwin/arch_setup.h
@@ -39,6 +39,9 @@ extern "C" int SM_main( int argc, char *argv[] );
 #ifndef MACOSX
 # define MACOSX
 #endif
+#ifndef __MACOSX__
+# define __MACOSX__
+#endif
 
 #define ArchSwap32(n) OSSwapInt32((n))
 #define ArchSwap24(n) (ArchSwap32((n)) >> 8)