My chess engine takes only a few seconds to calculatethe next move, so creating an own thread is some overkill.
What I need:
User has done his move, so update display, indicate that computer is
"thinking" for a few seconds, and then update display again. I think
that should be possible with g_idle_add(). Instead of the busy pointer
I may set a message to the window title.
Later I may consider indeed using a separate thread