anchor.diff:  stdenv.mkDerivation {
     name = "ocaml-${pname}-${version}";
   
  -  src = fetchurl {
  -    url = "https://github.com/ncannasse/${pname}/archive/${version}.tar.gz";
  -    sha256 = "10b55qf6mvdp11ny3h0jv6k6wrs78jr9lhsiswl0xya7z8r8j0a2";
  +  src = fetchFromGitHub {
  +    owner = "ncannasse";
  +    repo = "xml-light";
  +    rev = version;
  +    sha256 = "sha256-2txmkl/ZN5RGaLQJmr+orqwB4CbFk2RpLJd4gr7kPiE=";
     };
   
     buildInputs = [ ocaml findlib ];
  
positive.code: {stdenv, lib, fetchurl, ocaml, findlib}:
  let
    pname = "xml-light";
    version = "2.4";
  
negative.code:     homepage = "http://tech.motion-twin.com/xmllight.html";
      license = lib.licenses.lgpl21;
      maintainers = [ lib.maintainers.romildo ];
      platforms = ocaml.meta.platforms or [ ];
    };
  }
  