[MLton] compiler dependencies

[Stephen Weeks]

> > As to VC++, I've never tried it.  We don't use gcc for much when we're
> > using our native code generator, so it shouldn't be too hard to use
> > another C compiler in that case.  But I don't know why we would want
> > to.
> 
> Am I understanding you as saying you don't care about the Windows
> platform? 

No.  Simply that I don't know enough to know what's needed.

> I would think the motive for 'why someone would want to' is
> straightforward.

I don't know what is needed to generate executables for Windows.  If
gcc is sufficient, then I don't see why we should use VC++ (or some
other tool).  If gcc isn't sufficient, then obviously we need
something else.