gobject-introspection: support cross-compilation

[Artturin]

with this json-glib cross-compiles and the gir files exist, have not tested running any binaries on aarch64

nix build ".#pkgsCross.aarch64-multiplatform.json-glib"

#88222
#72868

https://github.com/void-linux/void-packages/blob/master/srcpkgs/gobject-introspection/template and the buildroot mk file were inspirations

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.11 Release Notes (or backporting 22.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[Mindavi]

Hmm, will we need to build such wrapper for each package using gobject-introspection?

[SuperSandro2000]

Only some formatting improvements. Thanks for trying to bring this forward. I really really appreciate it!

[Mindavi]

I do like this better than having it in json-glib at least :). Still need to try it out

[SuperSandro2000]

I think we are in a good state here now!

@Mindavi what do you think? Can we merge this soon?

[Artturin]

I think we are in a good state here now!
@Mindavi what do you think? Can we merge this soon?

I think we can merge this soon-ish. I want to do some testing, but I tried out an older version (from yesterday) and that was already looking promising. Let's also address the review comments 😄.

Just to get some idea of the status:

1. For any package _not_ using meson, we don't need to add the hook, right? It should work out of the box?

2. For any package using meson we need the hook because meson does it's own handing of gobject-introspection, correct?

I'm not really sure if we really want to make a separate hook or if we always want to do this when meson and gobject-introspection are both used. I think it would be more convenient and cause less friction if we could automatically add the cross-file when needed instead of having to explicitly define it.

In general, most of this is looking good!

The hook is not always needed even with meson, small example
json-glib doesn't need it while gtk3 does

[Mindavi]

Cool, yeah, if it's not always needed I think it's preferred to not have to have an emulator unless it's really needed.

[Mindavi]

Diff now LGTM

[Artturin]

Thanks everyone!