HEADS UP!!!

change the type of startupHaskell():

   void startupHaskell  ( int argc, char *argv[], void *init_root );

the extra parameter is a pointer to the initialisation function for
the root module in the program.  eg., Main.c now passes __init_Main for
this parameter.  It can be left as NULL if there is no root module.

This interface may need to be revised, since in some circumstances
there may be more than one "root module".

Sigbjorn: H/Direct will need some changes to stay in sync here.