Fix compiler warnings.

src/forward.c

@@ -670,6 +670,7 @@ int fast_retry(time_t now)
   return ret;
 }
 
+#if defined(HAVE_IPSET) || defined(HAVE_NFTSET)
 static struct ipsets *domain_find_sets(struct ipsets *setlist, const char *domain) {
   /* Similar algorithm to search_servers. */
   struct ipsets *ipset_pos, *ret = NULL;
@@ -690,6 +691,7 @@ static struct ipsets *domain_find_sets(struct ipsets *setlist, const char *domai
 
   return ret;
 }
+#endif
 
 static size_t process_reply(struct dns_header *header, time_t now, struct server *server, size_t n, int check_rebind, 
 			    int no_cache, int cache_secure, int bogusanswer, int ad_reqd, int do_bit, int added_pheader,