[MLton] MLton on Cygwin

[Matthew Fluet]

> I've made some progress getting MLton working on Cygwin again.
>
> I did see the errors that Tom and Neophytos sent, and I get exactly
> the same error as Neophytos when running MLton 20041109 on Cygwin
> 1.5.18-1.
>
> I decided to start from scratch and try to get the new (svn) version
> of MLton working on the new Cygwin rather than try to fix the old
> MLton.  I'm getting closer to having something working on that front.
> As I mentioned last month, there is some problem connected with our
> use of Virtual{Alloc,Free} for obtaining memory.

But, that doesn't appear to explain why the external call to gcc raises 
the signal or dll error.  (I get the error message that Tom gets.)

We know that MLton worked with Cygwin as of 20041109, which means that 
Cygwin has changed in the meantime.  My concern is that if upgrading 
Cygwin breaks MLton, then we run the risk of MLton breaking again the next 
time Cygwin updates.  We were "lucky" this time around, since it appears 
to have broken relatively recently, when we had a new release on the 
horizon.