anchor.diff:    };
   
     commonConfigureFlags =
  -    [ "--enable-optimize"
  -      #"--enable-profiling"
  -      (if debugBuild then "--enable-debug" else "--disable-debug")
  -      "--enable-strip"
  -      "--with-system-jpeg"
  +    [ "--with-system-jpeg"
         "--with-system-zlib"
         "--with-system-bz2"
         "--with-system-nspr"
  
positive.code:         xlibs.libXScrnSaver xlibs.scrnsaverproto pysqlite
          xlibs.libXext xlibs.xextproto sqlite unzip makeWrapper
          hunspell libevent libstartup_notification libvpx cairo
          gstreamer gst_plugins_base
        ];
  
      configureFlags =
  
negative.code:       "--with-system-libevent"
        "--with-system-libvpx"
        "--with-system-png"
        "--with-system-icu"
        "--enable-system-ffi"
        "--enable-system-hunspell"
        "--enable-system-pixman"
        "--enable-system-sqlite"
        "--enable-system-cairo"
        "--enable-startup-notification"
        # "--enable-content-sandbox"            # available since 26.0, but not much info available
        # "--enable-content-sandbox-reporter"   # keeping disabled for now
        "--disable-crashreporter"
        "--disable-tests"
        "--disable-necko-wifi" # maybe we want to enable this at some point
        "--disable-installer"
        "--disable-updater"
      ] ++ (if debugBuild then [ "--enable-debug" "--enable-profiling"]
                          else [ "--disable-debug" "--enable-release"
                                 "--enable-optimize" "--enable-strip" ]);
  
  
    xulrunner = stdenv.mkDerivation rec {
  