Rewrite examples - conservative server

/* have cmd line option to change this */
int af = AF_INET6; 
struct addrinfo hints, *res;
int s, i;

memset(&hints, 0, sizeof(hints));
hints.ai_family = af;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE;
error = getaddrinfo(NULL, "http", &hints, &res);
if (error)
    exit(1);
if (res->ai_next) {
    fprintf(stderr, "multiple addr");
    exit(1);
}
/* res has chain of wildcard addrs */
s = socket(res->ai_family, res->ai_socktype,
        res->ai_protocol);
if (s < 0)
    exit(1);
if (bind(s, res->ai_addr, res->ai_addrlen) < 0)
    exit(1);
listen(s, 5);
freeaddrinfo(res);