[m-rev.] for review: let host / target env types be overridden

[Zoltan Somogyi]

On Wed, 31 Dec 2025 15:22:39 +1100, Julien Fischer <jfischer at opturion.com> wrote:

> On Tue, 30 Dec 2025 at 04:08, Julien Fischer <jfischer at opturion.com> wrote:
> >
> > Let host / target env types be overridden.
> >
> > Let the host and target env types be overridden in the environment.
> > If not set in the environment, then they default to the values
> > determined by the configure script.
> >
> > Use this capability to let Mercury compilers built in one of the MSYS2
> > environments be usable from both the MSYS2 shell (via the mmc script) and
> > also from cmd.exe (via the mercury.bat batch file), _without_ requiring any
> > modifications to Mercury.config.
> 
> In the absence of any review comments, I intend to commit this later today.
> I have other changes that are waiting on it.

I had a look. I am totally unfamiliar with Windows/MSYS2, but it seems
ok to me.

Zoltan.