[MLton] mingwows

[Stephen Weeks]

Thanks to Wesley's latest patch for MinGW (from almost a month ago), I
have been able to build a binary MLton package for MinGW.  This
package is quite stable, passes all the regressions (that we would
expect on Windows), and self compiles, both within msys and via cross
compiling.  In fact, I'd say that the MinGW MLton is now more robust
than the Cygwin MLton, with the exception of some missing features.

I've put up an experimental MinGW package at

  http://mlton.org/Experimental

The package expects to live in /mingw/{bin,lib,share}, so unpacking it
in / within an msys shell does the right thing.

I haven't included the mlton.bat file, but am not opposed to doing so.
I just have no idea where the right place to put it, or if it's really
necessary.  Is it reasonable to expect that anyone who has MinGW also
has msys?  I also liked Wesley's early suggestion of having a small
front-end sml program instead of mlton.bat, since that would be more
robust and more portable.

I plan for MinGW to be part of the forthcoming public release, so if
you are interested in that platform, please try it out and send
suggestions for improvement.