anchor.diff:              '' else ''
                 echo "Checking that Nix can read nix.conf..."
                 ln -s $out ./nix.conf
  -              NIX_CONF_DIR=$PWD ${cfg.package}/bin/nix show-config >/dev/null
  +              NIX_CONF_DIR=$PWD ${cfg.package}/bin/nix show-config ${optionalString isNix23 "--no-net"} >/dev/null
               '')
         );
   
  
positive.code:           builders =
          ''}
          system-features = ${toString cfg.systemFeatures}
          ${optionalString (versionAtLeast nixVersion "2.3pre") ''
            sandbox-fallback = false
          ''}
          $extraOptions
  
negative.code:   nixVersion = getVersion nix;
  
    isNix20 = versionAtLeast nixVersion "2.0pre";
    isNix23 = versionAtLeast nixVersion "2.3pre";
  
    makeNixBuildUser = nr:
      { name = "nixbld${toString nr}";
  