if'def out private function ares__tvdiff(), it is not in use yet.

ares/ares__timeval.c

@@ -81,6 +81,7 @@ struct timeval ares__tvnow(void)
 
 #endif
 
+#if 0 /* Not used */
 /*
  * Make sure that the first argument is the more recent time, as otherwise
  * we'll get a weird negative time-diff back...
@@ -92,4 +93,5 @@ long ares__tvdiff(struct timeval newer, struct timeval older)
   return (newer.tv_sec-older.tv_sec)*1000+
     (newer.tv_usec-older.tv_usec)/1000;
 }
+#endif
 

ares/ares_private.h

@@ -279,7 +279,9 @@ int ares__read_line(FILE *fp, char **buf, int *bufsize);
 void ares__free_query(struct query *query);
 short ares__generate_new_id(rc4_key* key);
 struct timeval ares__tvnow(void);
+#if 0 /* Not used */
 long ares__tvdiff(struct timeval t1, struct timeval t2);
+#endif
 
 #define ARES_SWAP_BYTE(a,b) \
   { unsigned char swapByte = *(a);  *(a) = *(b);  *(b) = swapByte; }