anchor.diff:      # "ffmpeg" # https://crbug.com/731766
       # "harfbuzz-ng" # in versions over 63 harfbuzz and freetype are being built together
                       # so we can't build with one from system and other from source
  -  ] ++ optional (upstream-info.channel != "dev") "yasm";
  +  ] ++ optional (versionRange "0" "84") "yasm";
   
     opusWithCustomModes = libopus.override {
       withCustomModes = true;
  
positive.code:     ffmpeg libxslt libxml2
      # harfbuzz # in versions over 63 harfbuzz and freetype are being built together
                 # so we can't build with one from system and other from source
    ] ++ (if upstream-info.channel == "dev" then [ nasm ] else [ yasm ]);
  
    # build paths and release info
    packageName = extraAttrs.packageName or extraAttrs.name;
  
negative.code:       ln -s ${llvmPackages.llvm}/bin/llvm-ar    third_party/llvm-build/Release+Asserts/bin/llvm-ar
      '';
  
      gnFlags = mkGnFlags (optionalAttrs (versionRange "0" "84") {
        linux_use_bundled_binutils = false;
      } // {
        use_lld = false;
  