anchor.diff:  { stdenv, lib, fetchFromGitHub
   , fetchpatch
  -, asciidoc
   , brotli
   , cmake
  -, graphviz
  -, doxygen
   , giflib
   , gperftools
   , gtest
  
positive.code: , libwebp
  , openexr
  , pkg-config
  , python3
  , zlib
  }:
  
  stdenv.mkDerivation rec {
  
negative.code:   ];
  
    nativeBuildInputs = [
      cmake
      gtest
      pkg-config
    ] ++ lib.optionals buildDocs [
      asciidoc
      graphviz
      doxygen
      python3
    ];
  
    # Functionality not currently provided by this package
  