Re: SOS. No garbage-collection on exit!

[Matthew Flatt <mflatt@cs.utah.edu>]

Quoting Brent Fulgham:
> Speaking of garbage collection, what (if any) harm was the
> SCHEME_USE_FUEL macro designed to protect against?

Internally, SCHEME_USE_FUEL designates a point for potentially swapping
MzScheme threads and handling breaks.

In addition, for platforms where thread-swaps are not timed by an
interrupt, SCHEME_USE_FUEL decrements the current thread's "fuel"; when
a thread runs out of fuel, it's time to swap in another thread.

SCHEME_USE_FUEL is currently internal, but it looks like it should be
public. I'll fix that and document it.

Matthew