reading-server does not work if ipv6 is disabled

[fstshrk]

reading-server does not work if ipv6 is disabled, because it only tries a v6 socket:
int sock = socket(AF_INET6, SOCK_STREAM, 0);

It would be great if there was a -4 or -6 option to select the socket type or use a socket with fallback option to v4. In our environment, v6 is currently not supported.