[MLton] MLton rules! (was: filedes = int)

[Henry Cejtin]

No, I put the GMP support in to MLton exactly because I wanted fast large
multi-precision integers.  I need the speed.
I agree that you could re-implement the library using the same representation
in the compiler, because the compiler doesn't do any thing that much with
big integers, but why bother.  Also, why not take advantage of the speed.
Even more importantly, why depend on the format of libgmp numbers in a
separate implementation.