anchor.diff:  , fetchzip
   , optipng
   , cairo
  -, python3Packages
  +, python3
   , pkgconfig
   , pngquant
   , which
   , imagemagick
  +, zopfli
   }:
   
   let
  
positive.code:   };
  
    noto-fonts-emoji = let
      version = "unstable-2019-10-22";
    in stdenv.mkDerivation {
      pname = "noto-fonts-emoji";
      inherit version;
  
      src = fetchFromGitHub {
        owner = "googlei18n";
        repo = "noto-emoji";
        rev = "018aa149d622a4fea11f01c61a7207079da301bc";
        sha256 = "0qmnnjpp5lza6g5m3ki6hj46p891h9vl42k3acd0qw8i0jj5yn2c";
      };
  
      buildInputs = [ cairo ];
      nativeBuildInputs = [ pngquant optipng which cairo pkgconfig imagemagick ]
                       ++ (with python3Packages; [ python fonttools nototools ]);
  
      postPatch = ''
        sed -i 's,^PNGQUANT :=.*,PNGQUANT := ${pngquant}/bin/pngquant,' Makefile
        patchShebangs flag_glyph_name.py
      '';
  
      enableParallelBuilding = true;
  
negative.code:     meta = with lib; {
        inherit version;
        description = "Color and Black-and-White emoji fonts";
        homepage = "https://github.com/googlefonts/noto-emoji";
        license = with licenses; [ ofl asl20 ];
        platforms = platforms.all;
        maintainers = with maintainers; [ mathnerd314 ];
  