Bug#757876: freeciv-client-gtk: can't start a local game

[Jacob Nevins]

Xavier Cartron writes:
> - If I do 'freeciv-server -p 5557',, the server starts normally.

Enh. Of course the client might not be choosing 5557. It tries to find a
free port and tells the server to use that.
(Sure would have been useful if we (upstream) had thought to log the
port we were attempting to use, either in the client or in the
server...)

If the client had, for instance, a logical bug where it searched for the
first *used* port, or its test for free-ness always returned false
causing the port to wrap around, I guess that could cause this symptom.
(The relevant code is in utility/netintf.c:find_next_free_port().)

Is there anything unusual about your network stack? Lack of IP
connectivity, real IPv6 connectivity, non-default kernel options,
anything like that?