[m-rev.] for review: support optional package version information

[Zoltan Somogyi]

On 2023-09-09 00:43 +10:00 AEST, "Julien Fischer" <jfischer at opturion.com> wrote:
> library/library.m:
>     Add version/3, which returns the package version string in addition
>     to the version and fullarch strings.

I have a slight preference for separate predicates (or functions)
returning the Mercury version, the package version, and the fullarch,
but I can see that there is no point in switching to that now.
However, I think it would be better to add any NEW info, such as the
package version, as something you can get on its own.

> +    library.version(Version, Package, _FullArch),

See? You don't want to be forced to get everything at once,
with the risk of confusion about which arg means what.

The diff is otherwise fine.

Zoltan.