macOS build failure on unstable

[frekw]

Describe the bug
When trying to get rules_nixpgks up and running on unstable I ran across this. I guess it's being changed in nixpkgs.

      > unpacking 'https://github.com/NixOS/nixpkgs/archive/554be6495561ff07b6c724047bdd7e0716aa7b46.tar.gz' into the Git cache...
      > error:
      >        … while calling the 'derivationStrict' builtin
      >          at <nix/derivation-internal.nix>:37:12:
      >            36|
      >            37|   strict = derivationStrict drvAttrs;
      >              |            ^
      >            38|
      >
      >        … while evaluating derivation 'bazel-clang-wrapper-19.1.7-toolchain'
      >          whose name attribute is located at /nix/store/yw0wijix50n0y2ii15sk8kvnwgalpq6f-source/pkgs/stdenv/generic/make-derivation.nix:539:13
      >
      >        … while evaluating attribute 'buildCommand' of derivation 'bazel-clang-wrapper-19.1.7-toolchain'
      >          at /nix/store/yw0wijix50n0y2ii15sk8kvnwgalpq6f-source/pkgs/build-support/trivial-builders/default.nix:80:17:
      >            79|         enableParallelBuilding = true;
      >            80|         inherit buildCommand name;
      >              |                 ^
      >            81|         passAsFile = [ "buildCommand" ] ++ (derivationArgs.passAsFile or [ ]);
      >
      >        (stack trace truncated; use '--show-trace' to show the full, detailed trace)
      >
      >        error: darwin.libresolvHeaders has been removed; use `lib.getInclude darwin.libresolv

To Reproduce
Use rules_nixpkgs with unstable.

Expected behavior
For it to work.

Environment

• OS name + version: macOS 26.0
• Version of the code: 0.13.0

Additional context
Add any other context about the problem here.