diff --git a/src/md5.c b/src/md5.c
index 4671b90..cd0a717 100644
--- a/src/md5.c
+++ b/src/md5.c
@@ -17,6 +17,9 @@
 
 #include "md5.h"
 
+# if __BYTE_ORDER == __BIG_ENDIAN
+#define HIGHFIRST
+#endif
 
 #ifndef HIGHFIRST
 #define byteReverse(buf, len)	/* Nothing */