Use sk_namelookup to get FQDN host name.

It's silly to use the higher-level name_lookup(), because the way in
which they differ is that name_lookup() allows DNS lookups to be
deferred to the other side of a network proxy over which your
connection is travelling - and when you're trying to find out your own
host name for use as a database key, there's no _connection_ involved
at all, and no potential proxy either.

unix/ux_x11.c

@@ -78,8 +78,7 @@ int platform_make_x11_server(Plug *plug, const char *progname, int mindisp,
             char *hostname = get_hostname();
             if (hostname) {
                 char *canonicalname = NULL;
-                a_tcp = name_lookup(hostname, tcp_port, &canonicalname,
-                                    conf, addrtype, NULL, "");
+                a_tcp = sk_namelookup(hostname, &canonicalname, addrtype);
                 sfree(canonicalname);
             }
             sfree(hostname);