[project @ 1999-11-18 16:02:17 by sewardj]

Minor bugfixes for concurrency support in Hugs.

Evaluator.c: correctly handle case of entering a black hole.
Prelude.hs:  better exception catching in forkIO and primRunIO
GC.c:        (revert_dead_CAFs): don't ASSERT(0) on a dead CAF
             (I don't know why this assert was there)