integration of PolySpace mods into MLton

[Matthew Fluet]

> > > * Do you still need -stop s when compiling -native false?  We had
> > >   eliminated it.
> > 
> > As long as we can compile and link in other C files, this is OK.
> 
> Any additional files on the command line will be added in the final
> call to gcc that links to build the main executable.  So you can do
> things like "mlton z.sml foo.c".  Hopefully that is good enough.

This actually works as well for -On options (and -include and -L options).