NON-daemonic forking

[George Russell]

Einar Karlson, my predecessor, asked for daemonic forking as for Java.  In Java
you have ordinary threads and daemonic threads; the process ends when only daemonic
threads are still running.  The GHC team seem to have gone ahead and made all
forked thread daemonic!  So can we have ordinary threads back please?  Still,
daemonic threads are nice, and I wonder whether we should really have two
fork functions, since I can't right now think of a way of synthesising one from the 
other.