anchor.diff:  { stdenv
   , docbook-xsl
  -, docbook_sgml_dtd_31
  +, docbook_xml_dtd_44
   , fetchFromGitHub
   , libxslt
   , perlPackages
  
positive.code: 
    nativeBuildInputs = [
      docbook-xsl
      libxslt
    ];
  
  
negative.code: , libcap
  , libidn2
  , openssl
  }:
  
  let
    date = "2018-03-14";
    rev = "0b4f8f12ecd487314f2c4f3d27c1a11130df5e84";
  in
  stdenv.mkDerivation rec {
    name = "iputils-${date}";
  
    src = fetchFromGitHub {
      version = 6;
      owner = "iputils";
      repo = "iputils";
      inherit rev;
      sha256 = "fa15ac68a3546fcb30645e3c478b684d620251491e1ece0e5281dd43f711d9da";
    };
  
    postPatch = /* Fix hardcoded xsltproc path */ ''
  