python2.7: Return full path from find_library

[aneeshusa]

Motivation for this change

Fixes #7307. (Also fixes #33971 in a different way; would love to get both patches in.)

The upstream cpython patch to implement this behavior got reverted as it caused issues on some niche platforms, but I think Nixpkgs can punt on those issues for now.

cc @edolstra and @FRidh who have put in patches around Python's find_library previously.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option build-use-sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

---

[FRidh]

We should go through the patches and see where they can be merged. This file is touched in several patches. Furthermore, whether we get an absolute path back or not does not matter; occurrences of find_library should be patched with a hardcoded path to the library, because that is needed for during runtime.

[aneeshusa]

@FRidh I agree most cases should have a hardcoded path to the library. The point of this patch is to work for Salt, where the final Python file will both be used locally but also can be copied directly to a target system and used as part of salt-ssh. Since the target machine may not have Nix, we can't just hardcode the path to a Nix libcrypto.

I just used this patch to bootstrap several RPis via salt-ssh. #33971 will also address this in a different way if you prefer that.

I personally like to keep patches separate when possible to make it easier to update them.

[mmahut]

Are there any updates on this pull request, please?

[stale]

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[aneeshusa]

I am not using Salt or Python 2.7 any more.