anchor.diff:  
     nixVersion = getVersion nix;
   
  -  isNix20 = versionAtLeast nixVersion "2.0pre";
     isNix23 = versionAtLeast nixVersion "2.3pre";
   
     makeNixBuildUser = nr:
  
positive.code: 
      systemd.services.nix-daemon =
        { path = [ nix pkgs.utillinux config.programs.ssh.package ]
            ++ optionals cfg.distributedBuilds [ pkgs.gzip ]
            ++ optionals (!isNix20) [ pkgs.openssl.bin ];
  
          environment = cfg.envVars
            // { CURL_CA_BUNDLE = "/etc/ssl/certs/ca-certificates.crt"; }
  
negative.code:         restartTriggers = [ nixConf ];
        };
  
      # Set up the environment variables for running Nix.
      environment.sessionVariables = cfg.envVars //
        { NIX_PATH = cfg.nixPath;
        };
  
      environment.extraInit =
        ''
          if [ -e "$HOME/.nix-defexpr/channels" ]; then
            export NIX_PATH="$HOME/.nix-defexpr/channels''${NIX_PATH:+:$NIX_PATH}"
          fi
  