[MLton] x86-64 merge?

[Stephen Weeks]

> I don't have any strong reasons not to merge the branch.  

Great.  I say go for it when ready then.

> I don't think that it is feasible to finish the x86-64 port without
> going through a period where the build is broken (that is, I prefer
> to checkpoint incomplete progress), so I would like to keep (or
> re-branch) the x86-64 branch.

Sure.

> Also, I was hoping that someone could verify the x86-darwin port.

Speaking of which, are we waiting for a response from Reppy?  Perhaps
we should ping him.