Rewriting server side

Resolve name by getaddrinfo()
Use AI_PASSIVE to get wildcard sockaddr
We don't know address family, so need to resolve name before socket()

Try all returned addrinfo, ignore errors until we reach the end
Kernel may not have IPv6 support
Kernel may not be configured with IPv4/v6
DNS database may not be correct
Kernel may be imposing ordering constraint between bind(2)