L. Lynn Smith wrote on Wed, Nov 5, 2003 12:53 PM UTC:
Create a dummy position called 'post'. And place a Black Pawn in it.
Then with each move, change-owner this piece so that it switches sides
with each move. It should be the opposing side's piece at the start of
each move.
Then in the win-condition include the following:
(absolute-config (opponent Pawn)(post))
This should work fine. The condition will not be true until the opponent
has completed their move.