anchor.diff:    version = "${baseVersion}.${revision}";
   
     src = fetchurl {
  -    url = "http://download.qt-project.org/official_releases/qtcreator/${baseVersion}/${version}/qt-creator-opensource-src-${version}.tar.gz";
  -    sha256 = "0f2slaf579q2anflf524lbhmpwrwy3hzjfxzs10n44r7s7yc4dr5";
  +    url = "http://download.qt-project.org/official_releases/qtcreator/${baseVersion}/${version}/qt-creator-opensource-src-${version}.tar.xz";
  +    sha256 = "1n3ihky72p6q69n6c8s5hacq8rxdqmmr6msg89w5amwd17sam7p9";
     };
   
     buildInputs = [ qtbase qtscript qtquickcontrols qtdeclarative ];
  
positive.code:   '';
  
    postInstall = ''
      # Install desktop file
      mkdir -p "$out/share/applications"
      cat > "$out/share/applications/qtcreator.desktop" << __EOF__
      [Desktop Entry]
      Exec=$out/bin/qtcreator
      Name=Qt Creator
      GenericName=Cross-platform IDE for Qt
      Icon=QtProject-qtcreator.png
      Terminal=false
      Type=Application
      Categories=Qt;Development;IDE;
      __EOF__
      wrapQtProgram $out/bin/qtcreator
    '';
  
  
negative.code: with stdenv.lib;
  
  let
    baseVersion = "4.3";
    revision = "0";
  in
  
  stdenv.mkDerivation rec {
  