[MLton] upcoming release

[Matthew Fluet]

> > One issue is that having updated our sources to avoid the deprecated 
> > annotations, the sources now use annotations that are not known to MLton 
> > 20041109.  Hence, there are some warnings issued when compiling with an 
> > older verion of MLton, but they are benign.
> 
> Yeah.  Further, when bootstrapping from an old compiler we use
> mlton.cm, which avoids the annotation issue altogether.

True.  I encountered them when I bootstrapped from non-clean sources, 
where I had a "current" mlton sitting in build/bin.