anchor.diff:  
       # Set up the environment variables for running Nix.
       environment.sessionVariables = cfg.envVars //
  -      { NIX_PATH = concatStringsSep ":" cfg.nixPath;
  +      { NIX_PATH = cfg.nixPath;
         };
   
       environment.extraInit = optionalString (!isNix20)
  
positive.code:         type = types.listOf types.str;
          default =
            [
              "$HOME/.nix-defexpr/channels"
              "nixpkgs=/nix/var/nix/profiles/per-user/root/channels/nixos"
              "nixos-config=/etc/nixos/configuration.nix"
              "/nix/var/nix/profiles/per-user/root/channels"
  
negative.code:         if [ "$USER" != root -o ! -w /nix/var/nix/db ]; then
              export NIX_REMOTE=daemon
          fi
        '' + ''
          export NIX_PATH="$HOME/.nix-defexpr/channels''${NIX_PATH:+:$NIX_PATH}"
        '';
  
      nix.nrBuildUsers = mkDefault (lib.max 32 cfg.maxJobs);
  