[m-rev.] diff: Change git submodule update command in prepare.sh.

[Peter Wang]

On Wed, 12 Jul 2023 14:33:39 +1000 Julien Fischer <jfischer at opturion.com> wrote:
> 
> On Wed, 12 Jul 2023, Peter Wang wrote:
> 
> > prepare.sh:
> >    Don't pass --remote to the 'git submodule update'.
> >    We want the boehm_gc submodule to be checked out at the commit
> >    recorded in the mercury repository, not automatically update to the
> >    latest commit on the branch listed in .gitmodules. Similarly for
> >    libatomic_ops within the boehm_gc submodule.
> >
> >    Fix help message.
> 
> This presuambly ought to be on the release branch as well?

It's not necessary, but wouldn't hurt either.

Peter