🚀 go-pugleaf

This is the second report I've heard recently about problems with
gnuchess on an RS/6000.  You might try recompiling gnuchess with all
optimization turned off and see if that makes a difference.

The problem is almost certainly with gnuchess and not with xboard:
xboard does not have any code to tell whether you've won.  You can
tell for sure by looking at the text of the "illegal move" popup.  If
it says just "Illegal move," then xboard thought the move was illegal.
If it also gives the notation for the move (e.g., "Illegal move:
O-O"), then xboard thought the move was legal, but gnuchess said it
was illegal.  In the latter case you may also notice that xboard makes
the move on the board, then undoes it.

	--Tim
	  xboard maintainer