Bug#541461: xboard: needlessly depends on gnuchess

[h.g. muller]

Perhaps this deserves some explanation:

Historically XBoard has always had "GNU-mode" as default mode, which is 
obsolete
terminology for acting as interface to a chess engine. (Dating from the 
time that GNU-Chess
was the only existing XBoard compatible Chess engine.) The other modes, such as
game viewer or ICS client, had to be indicated with command-line options.
(-ncp = -noChessProgram and -ics, respectively.)

The major problem with XBoard is that the mode has to be chosen at 
start-up, and cannot
be switched afterwards. So it is easy to make sure it always starts up 
(using -ncp mode),
but it is no solution, as the user then almost always is stuck in a mode 
where he cannot
do what he wants, and has no option other than quiting xboard by himself. 
Starting in
ICS mode poses even more problems, as the ICS would have to be specified at 
startup,
and there are many different ICS. Plus that you then could not start up 
without a working
internet connection.

For this reason all previous XBoard packages have always used a default 
engine, which was
GNU Chess. Because it was possible to start XBoard with the use of 
command-line options
in different modes, it was never listed as a "dependency", like is remarked 
here. And even
if an engine would have been mandatory, there are zillions of alternatives 
to gnuchess.
So dependency on gnuchess would never be justified. We don't even recommend 
gnuchess
any longer; polyglot and the UCI engines are much more important to chess 
players.

Upstream we have switched from gnuchess to fairymax, because the latter can 
play many
of the variants that the new XBoard supports, including Chinese Chess, 
while GNU-Chess
only supported international Chess, and is not particularly good at it 
compared to alternatives
(fruit, glaurung, crafty, toga2). We wanted to prevent the situation where 
most XBoard menus
do not work and just draw the error message "not supported by first engine 
(gnuchess)".

H.G.Muller
upstream developer