[m-rev.] for review: fix duplicate installed grade checks

[Zoltan Somogyi]

On Fri, 10 Mar 2023 20:33:32 +1100 (AEDT), Julien Fischer <jfischer at opturion.com> wrote:
> > +        % We do this check only when InvokedByMake = no, because during
> > +        % compiler invocations that *set* --invoked-by-mmc-make,
> > +        % make_linked_target in make.program_target.m should have
> > +        % done it already.
> 
> A possible improvement here might to encode the value of --invoked-by-mmc-make
> in the op_mode, rather than have it be a separate flag that affects the op_mode.

I will look into this as a separate change. I followed all your
other suggestions.

> That's fine otherwise.

Thanks.

Zoltan.