[MLton] MLton on Cygwin

[Stephen Weeks]

> But, that doesn't appear to explain why the external call to gcc
> raises the signal or dll error.

True.  It appears to be unrelated.

> 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.

Of course, but I haven't seen anything to convince me that this is
anything other than a shared library changing behind our back.  We've
always had this problem and always will have this problem, on Cygwin
and on other OS'es.

> We were "lucky" this time around, since it appears to have broken
> relatively recently, when we had a new release on the horizon.

I don't see the situation as being different from upgrades of other
OS'es.  We don't guarantee to work except on the Cygwin we built
against (we should list the version on our Download page).  If someone
wants to upgrade to a new OS that we don't yet support, they have to
learn to build from the SVN or wait for a (possibly experimental)
release.  Again, nothing special about Cygwin here.

So, I think the right thing to focus on is getting the SVN Cygwin
working -- I would think the same even if we weren't near a new
release.  Once the SVN works, those on the bleeding edge of OS'es will
also have to be on the bleeding edge of MLton.