bug#48404: 28.0.50; "Invalid version syntax" errors with read-extended-command

[Tassilo Horn]

>> And that is assuming the developers of 3rd-party packages can have
>> some reasonable way of associating their versions with Emacs
>> versions, which I still think is a problem with no solution.
>
> They don't really need to.  They decide "we think people with Emacs 25
> shouldn't have this in their M-x TAX" and then put "26.1;Magit/1.2" in
> the string.

FWIW, as a 3rd-party package maintainer, I've never have the need to
define that some commands should not show up in completion with a
specific emacs version.  In auctex, we deal with emacs versions by just
requiring a minimal version (which gets bumpt very conservatively), and
that's about it.  But of course, YMMV.

In auctex, all our obsoletion versions are just version numbers "11.97"
like and represent the auctex version and our bug reports show that old
versions are still used much more often as one would expect.  So as long
as those "normal" versions don't cause the package version be compared
to the emacs version and just recently deprecated commands vanish from
completion, I'm neutral.

Bye,
Tassilo