anchor.diff:      libxml2
       lmdb
       ncurses
  -    openssl_1-0-2
  +    openssl
       pythonPackages.python
       pythonPackages.ply
       readline
  
positive.code:     optionals
      optionalString;
  
    version = "9.11.2-P1";
  in
  stdenv.mkDerivation rec {
    name = "bind${optionalString (suffix != "") "-${suffix}"}-${version}";
  
    src = fetchurl {
      url = "https://ftp.isc.org/isc/bind9/${version}/bind-${version}.tar.gz";
      multihash = "QmSvhppMPkAR76qgMwL9xDVMfSgpYnt7hgiZwyTuDZVfVk";
      hashOutput = false;
      sha256 = "cec31548832fca3f85d95178d4019b7d702039e8595d4c93914feba337df1212";
    };
  
    nativeBuildInputs = [
  
negative.code:     "--disable-fixed-rrset"
      "--enable-rpz-nsip"
      "--enable-rpz-nsdname"
      "--with-docbook-xsl=${docbook-xsl-ns}/share/xsl/docbook"
      "--with-idn=${idnkit}"
      "--without-atf"
  