time bug

[Stephen Weeks]

> Steve, I'm also curious if you were able to recreate the bug on your
> system with the mlton-20010321 version and the timeBug{1,2}.sml files.

Yes.  On my 400 MhZ machine, I see lots of messages printed for when GC > T.  On 
my 733 MhZ machine, I consistently get a Time exception.

I also can't quite get them working with the modification of your code that I
described yesterday.  I don't think it's worth figuring out, since we're going
to switch to getrusage everywhere.  Matthew, if you haven't done so already,
I'll take that on.