kaffe-0.8.x garbage collection problem (at least on m68k)

[Per Bothner]

> It would be nice if the gc would look at the current
> stack rather than the entire stack.  This would also have the effect
> of supressing false positives from stack garbage.

I just sent Tim some patches that solve part of this problem:
If you know the actual SP of a thread, it should now be trivial
to change the gc so it only scans the in-use part of the stack.
I just need code that given a thread ctx call tell me
(conservatively) what the SP is.

	--Per Bothner
Cygnus Solutions     bothner at cygnus.com     http://www.cygnus.com/~bothner