anchor.diff:  
     firefox = common {
       pname = "firefox";
  -    version = "40.0.3";
  -    sha1 = "6ddda46bd6540ab3ae932fbb5ffec8e9a85cab13";
  +    version = "41.0";
  +    sha1 = "0ce7a5ccdf671a6c98eaac07d06d49a895a99449";
     };
   
     firefox-esr = common {
  
positive.code:   name = "${pname}-${version}";
  
    src = fetchurl {
      url = "http://ftp.mozilla.org/pub/mozilla.org/firefox/releases/${version}/source/firefox-${version}.source.tar.bz2";
      inherit sha1;
    };
  
  
negative.code:       "--disable-installer"
        "--disable-updater"
        "--enable-jemalloc"
        "--disable-gconf"
      ]
      ++ lib.optional enableGTK3 "--enable-default-toolkit=cairo-gtk3"
      ++ (if debugBuild then [ "--enable-debug" "--enable-profiling" ]
  