[m-rev.] for review: delete obsolete procedures from string module

[Peter Wang]

On Wed, 13 Apr 2022 17:53:19 +1000 "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> So we need to choose a course of action.
> 
> One: make this new warning conditional on a new option, and disable this option
> in modules where the new warning would cause compilation to fail through
> --halt-at-warn. This would disable the warning in some of the modules where
> we could benefit from it, such as string.m itself.
> 
> Two: delete the modes from clauses for predicates with foreign_procs.
> 
> Three: do not generate the warning for predicates that also have foreign_procs.
> This cannot be done with the current architecture of make_hlds, because we add
> all clauses before we add any foreign_procs.
> 
> Four: the status quo, with no new warning at all.
> 
> I prefer two. Opinions?

I agree with two.

Since this is a style warning, there should be an option to turn it off,
implied by --inhibit-style-warnings.

Peter