binutils: fix cross compilation from darwin

[thefloweringash]

The libtool patch is required to correctly invoke the linker while
building, so it should depend on the build toolchain.

Description of changes

Addressing breakage reported in #134917 (comment)

This is only part of the story. There's still a problem with glibc and separateDebugInfo. If I turn that off I can build pkgsCross.aarch64-multiplatform.hello from x86_64-darwin via rosetta.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin (via rosetta)
  • 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/)
• 22.05 Release Notes (or backporting 21.11 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.

[lovesegfault]

LGTM, thanks for the fix!

[lovesegfault]

I imagine it needs to hit staging, not master?

[lovesegfault]

Well, seems like it doesn't trigger as many rebuilds as I thought.

I'm going to merge it.

[thefloweringash]

Well, seems like it doesn't trigger as many rebuilds as I thought.

Fortunately it only affects cross, so very few rebuilds.

Hydra evaluation to see the effects: https://hydra.nixos.org/eval/1756673