fix socket data type

tests/server/resolve.c

@@ -131,8 +131,8 @@ int main(int argc, char *argv[])
   else {
 #ifdef ENABLE_IPV6
     /* Check that the system has IPv6 enabled before checking the resolver */
-    int s = socket(PF_INET6, SOCK_DGRAM, 0);
-    if(s == -1)
+    curl_socket_t s = socket(PF_INET6, SOCK_DGRAM, 0);
+    if(s == CURL_SOCKET_BAD)
       /* an ipv6 address was requested and we can't get/use one */
       rc = -1;
     else {