anchor.diff:    # occasional build problems if one has too many cores (like on Hydra)
     # @vcunat has been unable to find a *reliable* fix
     enableParallelBuilding = false;
  +
  +  NIX_CFLAGS_COMPILE = optionalString stdenv.isDarwin
  +    "-I${glib}/include/glib-2.0 -I${glib}/lib/glib-2.0/include";
  +
  +  NIX_LDFLAGS = optionalString stdenv.isDarwin
  +    "-lglib-2.0";
  +
  +  preBuild = optionalString stdenv.isDarwin ''
  +    # resolve "extra qualification on member" error
  +    sed -i 's/struct ::TabletProximityRec;/struct TabletProximityRec;/' \
  +      src/gui/kernel/qt_cocoa_helpers_mac_p.h
  +  '';
   
     crossAttrs = let
       isMingw = stdenv.cross.config == "i686-pc-mingw32" ||
  
positive.code:     '';
  
    propagatedBuildInputs =
      [ libXrender libXrandr libXinerama libXcursor libXext libXfixes
        libXv libXi libSM
      ]
      ++ optional (stdenv.lib.lists.elem stdenv.system stdenv.lib.platforms.mesaPlatforms) mesa
      ++ optional ((buildWebkit || buildMultimedia) && stdenv.isLinux ) alsaLib
      ++ [ zlib libpng openssl dbus.libs freetype fontconfig glib ]
      ++ optionals (buildWebkit || buildMultimedia) [ gstreamer gst_plugins_base ];
  
    # The following libraries are only used in plugins
  
negative.code:         inherit gtk gdk_pixbuf;
        });
  
    preConfigure = ''
      export LD_LIBRARY_PATH="`pwd`/lib:$LD_LIBRARY_PATH"
      configureFlags+="
        -docdir $out/share/doc/${name}
        -plugindir $out/lib/qt4/plugins
        -importdir $out/lib/qt4/imports
        -examplesdir $out/share/doc/${name}/examples
        -demosdir $out/share/doc/${name}/demos
        -datadir $out/share/${name}
        -translationdir $out/share/${name}/translations
      "
    '' + optionalString stdenv.isDarwin ''
      export CXX=clang++
      export CC=clang
      sed -i 's/QMAKE_CC = gcc/QMAKE_CC = clang/' mkspecs/common/g++-base.conf
      sed -i 's/QMAKE_CXX = g++/QMAKE_CXX = clang++/' mkspecs/common/g++-base.conf
    '';
  
    prefixKey = "-prefix ";
    configureFlags =
  