[m-rev.] for review: put .module_dep and .prof files into grade-specific subdirs

[Zoltan Somogyi]

On Sun, 4 Aug 2024 16:05:16 +1000, Julien Fischer <jfischer at opturion.com> wrote:
> On that basis, I think a brief entry in the NEWS file describing where
> .prof files
> will now be placed is worthwhile.

While trying to write that NEWS.md entry, I realized something.
The call graph of a module is in general grade-dependent,
e.g. because there can be additional entries if the current grade
selects the Mercury definition of a predicate vs a grade that selects
a foreign_proc version. However, while I can see that such call-graph-affecting
differences are possible between two arbitrarily-picked grades, I cannot see
how any such differences are possible between two grades that both
call for mprof profiling. This is because mprof profiling implies (a) targeting C,
and (b) using the LLDS backend, which in turn implies that all mprof grades
will have the same call graph.

Since this implies that .prof files cannot actually differ between grades
(except by existing in mprof grades and not existing in other grades),
I am backing out the .prof file part of the change, and adding a comment
describing the above reasoning to the non-grade-specific classification
of the .prof extension.

> The diff itself is fine.

Thanks for the review.

Zoltan.