[LyX/master] Add support for zref-clever and zref-vario

[Jürgen Spitzmüller]

Am Montag, dem 24.03.2025 um 08:28 +0000 schrieb José Matos:
> I suspect that Riki is using the same version as I do:
> 
> Texlive 2023 (on Fedora)
> zref-clever 2023-02-21 v0.3.6 Clever LaTeX cross-references based on
> zref

I see. The \zlabel requirement has been dropped with 
v0.4.0 (2023-06-14). Current (with TL 25) is v0.5.1 (2024-11-28).

I think we should require this version at least given how new the
package is (and how much effort it would be to support these older
versions properly). I assume this will have settled also in the more
conservative distributions before LyX 2.5 is out.

I can add a version test and disable zref support for these older
versions if you want.

-- 
Jürgen