calling Socket.bind() with an undefined hostname parameter would result in a
getaddrinfo() failure, e.g. on Windows, WSAHOST_NOT_FOUND 11001
The ircd.js passes the value of server.interface_ip_address to socket.bind()
and when run from jsexec, this property is not defined. So you couldn't run the
ircd from jsexec or you'd get "!Error 0 binding socket to TCP port xxx".
Also now setting the socket last_error value upon getaddrinfo() failure so
if there is a failure, the error message won't include the erroneous "Error 0".