Adding useLLVM to a nixos system flake

1

nixpkgs.crossSystem.useLLVM = true results in an error saying I need to replace it with hostPlatform (because crossSystem is a legacy attribute). However the following causes a deeper error.

{...}: {
  nixpkgs.hostPlatform = {
    system = "x86_64-linux";
    useLLVM = true;
    linker = "lld";
  };
}

     error: attribute 'version' missing
       at «github:tinted-software/nixpkgs/0b00c2e7aaaa0bffa296e7ce98f23b1554743ced?narHash=sha256-8APHgVuJ4VoE5tVDxPJo64ZGo5ovIB5J6gGF4N6rVYY%3D»/pkgs/stdenv/linux/default.nix:557:51:
          556|             pname = prevStage.bintools.bintools.pname + "-patchelfed-ld";
          557|             inherit (prevStage.bintools.bintools) version;
             |                                                   ^
          558|             passthru = { inherit (prevStage.bintools.passthru) isFromBootstrapFiles; };
warning: could not build a newer version of nixos-rebuild, using current version

I’m not sure how Tristan managed to get this to work in nixpkgs-llvm-ws… because when I use _module.args.pkgs like he did it complains that it’s already defined in a nixos module from nixpkgs.
Ideally the missing attribute version error could be solved but I have no idea what a fix in nixpkgs itself would look like.