* guix/scripts/publish.scm (show-help, %options): Add --listen. (getaddrinfo*): New procedure. (%default-options): Add 'address'. (open-server-socket): Replace 'addr' and 'port' with 'address', a sockaddr. (guix-publish): Adjust accordingly. Augment "publishing" message with the actual address. * doc/guix.texi (Invoking guix publish): Document it.