anchor.diff:  { stdenv
   , buildPythonPackage
   , cython
  -, fetchFromGitHub
  -#, fetchPyPi
  +, fetchPyPi
   , isPy3
   , isPyPy
   , lib
  
positive.code:     "-I${greenlet}/include/${python.executable}${if isPy3 then "m" else ""}"
    ];
  
    buildDirCheck = false;  # FIXME
  
    meta = with lib; {
      description = "Coroutine-based networking library";
      homepage = http://www.gevent.org/;
  
negative.code:   inherit (lib)
      optionals;
  
    version = "1.3.7";
  in
  buildPythonPackage rec {
    name = "gevent-${version}";
  
    src = fetchPyPi {
      package = "gevent";
      inherit version;
      sha256 = "3f06f4802824c577272960df003a304ce95b3e82eea01dad2637cc8609c80e2c";
    };
  
    nativeBuildInputs = [
  