anchor.diff:    enableOfficialBranding ? false
   }:
   
  -let version = "31.2.0"; in
  +let version = "31.4.0"; in
   let verName = "${version}"; in
   
   stdenv.mkDerivation rec {
  
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.
  