anchor.diff:  
     src = fetchurl {
       url = "ftp://ftp.mozilla.org/pub/thunderbird/releases/${verName}/source/thunderbird-${verName}.source.tar.bz2";
  -    sha1 = "87dff89388bd7ec51876e1bdbd82bc3fe60006b6";
  +    sha1 = "00b55e28f55b84e3cd257407d797e07a363aeef8";
     };
   
     buildInputs = # from firefox30Pkgs.xulrunner, but without gstreamer and libvpx
  -    [ pkgconfig libpng gtk perl zip libIDL libjpeg zlib bzip2
  +    [ pkgconfig which libpng gtk perl zip libIDL libjpeg zlib bzip2
         python dbus dbus_glib pango freetype fontconfig xlibs.libXi
         xlibs.libX11 xlibs.libXrender xlibs.libXft xlibs.libXt file
         alsaLib nspr nss libnotify xlibs.pixman yasm mesa
  
positive.code: { stdenv, fetchurl, pkgconfig, m4, gtk, pango, perl, python, zip, libIDL
  , libjpeg, libpng, zlib, dbus, dbus_glib, bzip2, xlibs
  , freetype, fontconfig, file, alsaLib, nspr, nss, libnotify
  , yasm, mesa, sqlite, unzip, makeWrapper, pysqlite
  
negative.code:       "--disable-pulseaudio"
      ] ++ (if debugBuild then [ "--enable-debug" "--enable-profiling"]
                          else [ "--disable-debug" "--enable-release"
                                 "--disable-debug-symbols"
                                 "--enable-optimize" "--enable-strip" ])
      ++ [
        "--disable-javaxpcom"
        "--enable-stdcxx-compat" # Avoid dependency on libstdc++ 4.7
      ]
      ++ stdenv.lib.optional enableOfficialBranding "--enable-official-branding";
    in ''
      mkdir -p objdir/mozilla
      cd objdir
      echo '${stdenv.lib.concatMapStrings (s : "ac_add_options ${s}\n") configureFlags}' > .mozconfig
      echo 'ac_add_options --prefix="'"$out"'"' >> .mozconfig
      echo 'mk_add_options MOZ_MAKE_FLAGS="-j'"$NIX_BUILD_CORES"'"' >> .mozconfig
      echo 'mk_add_options MOZ_OBJDIR="'`pwd`'"' >> .mozconfig
  
      export MOZCONFIG=`realpath ./.mozconfig`
  
      patchShebangs ../mozilla/mach
      ../mozilla/mach configure
    '';
  
    buildPhase =  "../mozilla/mach build";
  
    installPhase =
      ''
        ../mozilla/mach install
  
        rm -rf $out/include $out/lib/thunderbird-devel-* $out/share/idl
  
        # Create a desktop item.
  