Migrate away from outdated vala versions

[Mic92]

Issue description

We currently have vala_0_23, vala_0_26, vala_0_26 and vala_0_28 in our repository that are no longer maintained upstream.

The current versions maintained upstream are: 0.34.13, 0.36.8 and 0.38.4

related to #32795

[Mic92]

I talked with upstream and they recommend to set 0.38.4 as default vala version, since it comes with many bugfixes.

UPDATE we already advertise 0.38.x as default.

[jtojnar]

I have opened a pull request fixing this.

• vala_0_23:
  • ccnet
  • finalterm also builds with 0.26, unmaintained there is also a fork but it does not build
  • giv
  • gmpc
  • libappindicator
  • libindicate
  • libosinfo
  • libunity also builds with 0.26, hideously outdated
  • midori also builds with 0.34
  • seafile-shared
  • synapse also builds with 0.34
• vala_0_26:
  • vanubi also builds with 0.28
• vala_0_28:
  • shotwell
  • valum
• vala_0_34:
  • deepin-terminal
  • gencfsm
  • libskk

So now we have

• vala_0_26:
  • finalterm
  • libunity
• vala_0_28:
  • vanubi
• vala_0_34:
  • midori
  • synapse

allowing us to drop vala_0_23.

If we want to get rid of more, we can move all of them to vala_0_26.

[Mic92]

Is libunitystill a thing? Did not ubuntu dropped unity development?

[jtojnar]

I do not know, the last update was in 2012 and it does not seem to be used anywhere in nixpkgs, it is probably okay to drop it.

[Mic92]

I would say it is safe to do so.

[jtojnar]

Actually, why not just change finalterm and vanubi to vala_0_38 and mark them with meta.broken = true?