anchor.diff:        mv -v "$celt_unpack_dir" celt-0.7.0-src/
       popd
   
  -    mkdir -pv themes/Mumble/
  -    cp -rv ${mumble-theme}/* themes/Mumble/
  +    pushd themes/
  +      unpackFile '${mumble-theme}'
  +      mumble_theme_unpack_dir="$(
  +        find . -type d -regextype sed -regex '\./mumble-theme-[a-z0-9]\{40\}'
  +      )"
  +      mv -v "$mumble_theme_unpack_dir"/* Mumble/
  +    popd
     '' + optionalString (config == "murmur" && ice != null) ''
       sed -i 's,/usr,${ice},g' src/murmur/murmur_ice/murmur_ice.pro
     '' + ''
  
positive.code:     optionals
      optionalString;
  
    mumble-theme = stdenv.mkDerivation {
      name = "mumble-theme-2017-11-26";
  
      src = fetchFromGitHub {
        version = 5;
        owner = "mumble-voip";
        repo = "mumble-theme";
        rev = "212f8e336d3c2b385c10a7462ceedb88919edd00";
        sha256 = "fca086c622b6cde4530647b5c3fa7b05e50adfdbb99705df54efbc6c18668b7f";
      };
  
      installPhase = ''
        mkdir -pv "$out"
        cp -rv . $out/
      '';
    };
  
    celt_mumble-src = fetchFromGitHub {
  
negative.code:     mv -v 3rdparty/qqbonjour-src/ 3rdparty-new/
      mv -v 3rdparty/smallft-src/ 3rdparty-new/
  
      # Remove the original 3rdparty directory to ensure vendored sources are
      # not used.
      rm -rv 3rdparty
      mv -v 3rdparty-new 3rdparty
  