[MLton] possible IntInf bug

[Stephen Weeks]

> Henry, could you take a look at the toChunkR function in
> basis-library/integer/int-inf.sml?  I am testing out a new feature
> that detects unused variables, and it detects that the variable
> "cread" defined on line 636 is unused.  I looked into the CVS and that
> was the case with the initial commit as well.  Is it a bug?

Here's a couple more possible bugs in IntInf.

Warning: <basis>/integer/int-inf.sml 693.22: unused variable: shift
Warning: <basis>/integer/int-inf.sml 737.7: unused variable: toX