Server rewrite, lazy - After the rewrite

s = socket(res->ai_family, res->ai_socktype,
        res->ai_protocol);
if (s < 0)
    exit(1);
 #ifdef IPV6_V6ONLY
if (res->ai_family == AF_INET6 &&
    setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0) {
    close(s);
    continue;
}
 #endif
if (bind(s, res->ai_addr, res->ai_addrlen) < 0)
    exit(1);
listen(s, 5);
freeaddrinfo(res);