nixos/stage-1: build extraUtils without compiler

  # copy what we need.  Instead of using statically linked binaries,

  # we just copy what we need from Glibc and use patchelf to make it

  # work.

  extraUtils = pkgs.runCommandCC "extra-utils"

  extraUtils = pkgs.runCommand "extra-utils"

    { nativeBuildInputs = [pkgs.buildPackages.nukeReferences];

      allowedReferences = [ "out" ]; # prevent accidents like glibc being included in the initrd

    }