anchor.diff:            $wgUploadDirectory = "${config.uploadDir}";
           ''}
   
  +        ${optionalString (config.defaultSkin != "") ''
  +          $wgDefaultSkin = "${config.defaultSkin}";
  +        ''}
  +
           ${config.extraConfig}
         ?>
       '';
  
positive.code:       sha256 = "1d8afbdh3lsg54b69mnh6a47psb3lg978xpp277qs08yz15cjf7q";
      };
  
      buildPhase = "true";
  
      installPhase =
        ''
  
negative.code:       default = throw "You must specify `uploadDir'.";
        example = "/data/mediawiki-upload";
        description = "The directory that stores uploaded files.";
      };
  
      defaultSkin = mkOption {
        default = "standard";
        example = "nostalgia";
        description = "Default skin: you can change the default skin.";
      };
  
      extraConfig = mkOption {
  