Make forkProcess work with +RTS -N

Consider this experimental for the time being.  There are a lot of
things that could go wrong, but I've verified that at least it works
on the test cases we have.

I also did some API cleanups while I was here.  Previously we had:

Capability * rts_eval (Capability *cap, HaskellObj p, /*out*/HaskellObj *ret);

but this API is particularly error-prone: if you forget to discard the
Capability * you passed in and use the return value instead, then
you're in for subtle bugs with +RTS -N later on.  So I changed all
these functions to this form:

void rts_eval (/* inout */ Capability **cap,
               /* in    */ HaskellObj p,
               /* out */   HaskellObj *ret)

It's much harder to use this version incorrectly, because you have to
pass the Capability in by reference.

1 files changed, 1 insertions, 1 deletions

diff --git a/rts/RtsMain.c b/rts/RtsMain.c
index 0f6ca82382..2084435f16 100644
--- a/rts/RtsMain.c
+++ b/rts/RtsMain.c
@@ -60,7 +60,7 @@ static void real_main(void)
     /* ToDo: want to start with a larger stack size */
     { 
 	Capability *cap = rts_lock();
-	cap = rts_evalLazyIO(cap,progmain_closure, NULL);
+        rts_evalLazyIO(&cap,progmain_closure, NULL);
 	status = rts_getSchedStatus(cap);
 	taskTimeStamp(myTask());
 	rts_unlock(cap);