{libllvm,isl,libiberty,libmpc}: fix references to /usr/bin/uname on native FreeBSD

[rhelmot]

We've all heard this story before. Old versions of gnu config scripts hardcode the /usr/bin/uname filename in the FreeBSD build system code path. Upgrade them so this stops happening. See #313496 for context.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
  • x86_64-freebsd
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• 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/)
• 25.05 Release Notes (or backporting 24.11 and 25.05 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
• Fits CONTRIBUTING.md.

---

Add a 👍 reaction to pull requests you find important.

[sternenseemann]

Seems okay to me, but maybe it's wiser to add updateAutotoolsGnuConfigScriptsHook to stdenv's extraNativeBuildInputs by default like we use for Linux? I would expect that this nuclear option would work better overall for a platform with a limited number of maintainers.

[rhelmot]

That would be really excellent! I was told explicitly to not do that when I submitted my first draft of the FreeBSD stdenv rewrite :)

[sternenseemann]

updateAutotoolsGnuConfigScriptsHook only looks in ., so instead of using sourceRoot to change directory after unpackPhase we would need to cd in preConfigure to make it work…

Alternatively we could make the directory configurable in the setup hook 🤔

[sternenseemann]

That would be really excellent! I was told explicitly to not do that when I submitted my first draft of the FreeBSD stdenv rewrite :)

Interesting, what was the reasoning given? FTR, #237968 added it for Linux. I think the inclusion in the Linux stdenv also actively reduces the amount of packages that explicitly request it.

I also don't necessarily like running the hook by default, but given that we do it for Linux already…

[rhelmot]

#311760 (comment)

The logic is that it will be impossible to remove later.