Output holds and windows

[Howard I. Cannon <HIC at MIT-MC>]

cc: AGRE at MIT-AI, BUG-LISPM at MIT-AI

Yes, perhaps having a enu around would be a good iea, and it would be 
basically trivial to do I suspect.  In the new window system, output hold
is just a message sent to a window, so....(actually, the standard handler
is pretty hairy, allowing you to send an arbitrary message to the window
when it tries to go into output hold..)