Add zelus and zelus-gtk 2.1 packages

[gbdrt]

These packages contains the Zelus compiler (package zelus) and optional gtk dependent librairies (zelus-gtk)
https://zelus.di.ens.fr/

[camelus]

Commit: b596a98

Hello @gbdrt! I believe this is your first contribution here. Please be nice, reviewers!

☀️ All lint checks passed b596a98

• These packages passed lint tests: zelus-gtk.2.1, zelus.2.1

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☀️ Installability check (+2)

• new installable packages (2): zelus.2.1 zelus-gtk.2.1

[gbdrt]

I don't understand why the build keeps failing on archlinux. I tried to add the missing dependencies, but:

• I don't understand why these packages are required
• The build is still failing with these explicit depexts.

Am I missing something?

[gbdrt]

Ok, making progress...
I removed the graphics dependencies, but now it is complaining about a missing gtk+.
Do I need to add it as a depexts? It looks like other packages depending on lablgtk do not need this.

Thanks for you help.

[kit-ty-kate]

this link is not accessible

[kit-ty-kate]

dune should not be tagged as a build dependency (see ocaml/dune#2147)

[kit-ty-kate]

If you are planning to release the two packages together, I would highly encourage you to use {= version}. If not, feel free to revert this change.

[kit-ty-kate]

gtksourceview-2.0 is getting really old and is not supported by an increasing number of distributions, it might be more future-proof to switch to gtksourceview3 in next release

[kit-ty-kate]

The PR should be good to go after that. Could you review my change and return them in the opam file upstream if they seem correct to you?

[gbdrt]

Thanks a lot!
I just pushed the updated version (with small fixes in the descriptions).
I also removed the dependencies to gtksourceview. We do not really need it, I wanted to see if it could solve the build failure on archlinux.

[kit-ty-kate]

Looks good now, thanks! (note that gtk2 itself is also quite old, though better supported across distributions than its sublibraries)