Fixed ret type warning;

ndbuf.c

@@ -34,7 +34,7 @@ static inline uint64_t ntohll(uint64_t n)
 #ifdef WORDS_BIGENDIAN
   return n;
 #else /* WORDS_BIGENDIAN */
-  return (((uint64_t)(n) << 56) | \
+  return (uint64_t)(((uint64_t)(n) << 56) |                      \
          (((uint64_t)(n) << 40) & 0xff000000000000ULL) | \
          (((uint64_t)(n) << 24) & 0xff0000000000ULL) | \
          (((uint64_t)(n) << 8)  & 0xff00000000ULL) | \