diff --git a/libmpcodecs/native/rtjpegn.c b/libmpcodecs/native/rtjpegn.c
index de72e5bd8e..d14843d4a1 100644
--- a/libmpcodecs/native/rtjpegn.c
+++ b/libmpcodecs/native/rtjpegn.c
@@ -26,7 +26,7 @@
 #include <string.h>
 
 #include "config.h"
-#ifdef HAVE_MMX
+#if HAVE_MMX
 #define MMX
 #endif