time bug

[Matthew Fluet]

> > 2. src/lib/mlton/basic/times.{sig,sml}
> >    src/mlton/control/control.sml
> ...
> > I updated /src/lib/mlton/basic/times.{sig,fun} with timesPre and
> > timesPost, and bound times to timesPre for compatibility.
> 
> Makes sense.  Another solution would be to have a single routine that returns
> times, like:
> 
>    val MLton.ProcEnv.times: unit -> {elapsed: Time.time,
> 				     cstime: Time.time,
> 				     cutime: Time.time,
> 				     gc: Time.time,
> 				     stime: Time.time,
> 				     utime: Time.time}

Wouldn't this suffer from the same problem?  Either we query
gcState.gcTime before or after a call to the times() "C" function.  We
can't write a gc.c function that returns that whole structure and import
it as a _ffi.  I suppose we could set it up in the same way Posix/Tms.c is
implemented; a side effecting _ffi call to atomically store all of the
sub-fields and then individually get each one.

But, I think there is a negligible amount of code duplication in the way
things are set up right now.