[MLton] unused variables in MLton

[Stephen Weeks]

> What is the problem with building the saved world as part of the package
> installation?

That should be doable.  The only problem is that it takes time to
figure out how to do it for all our package formats, and what do we do
with the tgz?  I suspect in the amount of time to do all that, I could
get most of -{load,save}-basis done.

> I don't think that it is a huge problem, but if the idea is using MLton
> without SML/NJ then something really has to get done eventually.

Agreed.