lib: add __BYTE_ORDER to md5.c

Signed-off-by: Karel Zak <kzak@redhat.com>

lib/md5.c

@@ -14,11 +14,16 @@
  * needed on buffers full of bytes, and then call MD5Final, which
  * will fill a supplied 16-byte array with the digest.
  */
+#include <endian.h>
 #include <string.h>		/* for memcpy() */
 
 #include "md5.h"
 
-#ifndef HIGHFIRST
+#if !defined __BYTE_ORDER || !(__BYTE_ORDER == __LITTLE_ENDIAN) && !(__BYTE_ORDER == __BIG_ENDIAN)
+#error missing __BYTE_ORDER
+#endif
+
+#if (__BYTE_ORDER == __LITTLE_ENDIAN)
 #define byteReverse(buf, len)	/* Nothing */
 #else
 void byteReverse(unsigned char *buf, unsigned longs);