diff --git a/src/osd/sdl/sdlprefix.h b/src/osd/sdl/sdlprefix.h
index 9ba0001ccc5..3efd521fbe9 100644
--- a/src/osd/sdl/sdlprefix.h
+++ b/src/osd/sdl/sdlprefix.h
@@ -79,4 +79,9 @@ struct _IO_FILE {};  //_IO_FILE is an opaque type in the emscripten libc which m
 #undef _FORTIFY_SOURCE
 #endif
 
+// nasty hack to stop altivec #define vector/bool/pixel screwing us over
+#if defined(__ALTIVEC__) && !defined(__APPLE_ALTIVEC__)
+#define __APPLE_ALTIVEC__ 1
+#endif
+
 #endif /* SDLMAME_UNIX */