[MLton] dropping ckit and MLRISC libraries from MLton package

[Matthew Fluet]

> I am currently building a MLton Debian package to fix bug #394981.  I
> am encountering problems with the MLRISC, ckit, and SML/NJ libraries.
> Lintian reports the warnings and errors below.  Separately from the
> question of fixing them, I wonder whether we should include the MLRISC
> and ckit libraries at all.  They are not widely used.  And, as we are
> moving along with the new library project, perhaps those should be
> moved to "org/smlnj/".  I think the SML/NJ library should go there
> too, although I would like to include it with MLton since it is more
> widely used.
>
> Thoughts?

I don't object to moving them.  I prefer to keep them in the form of pairs 
of a .tgz and a .patch file, since it helps to keep them in sync with 
SML/NJ.