anchor.diff:    ] ++ lib.optional withSystemd "-DWITH_SYSTEMD=ON";
   
     meta = with lib; {
  -    description = "An open source MQTT v3.1/3.1.1 broker";
  +    description = "An open source MQTT v3.1/3.1.1/5.0 broker";
       homepage = "https://mosquitto.org/";
       license = licenses.epl10;
       maintainers = with maintainers; [ peterhoeg ];
  
positive.code: { stdenv, lib, fetchFromGitHub, cmake, docbook_xsl, libxslt
  , openssl, libuuid, libwebsockets_3_1, c-ares, libuv
  , systemd ? null, withSystemd ? stdenv.isLinux }:
  
  stdenv.mkDerivation rec {
    pname = "mosquitto";
    version = "1.6.12";
  
    src = fetchFromGitHub {
      owner  = "eclipse";
      repo   = "mosquitto";
      rev    = "v${version}";
      sha256 = "0y9jna2p7wg57vv2g6ls1dj6w89vaw828y9z1wb3vwz1yhvs35s8";
    };
  
    postPatch = ''
  
negative.code:         --replace http://docbook.sourceforge.net/release/xsl/current ${docbook_xsl}/share/xml/docbook-xsl
      done
  
      # the manpages are not generated when using cmake
      pushd man
      make
      popd
    '';
  
    nativeBuildInputs = [ cmake docbook_xsl libxslt ];
  
    buildInputs = [
      c-ares
      cjson
      libuuid
      libuv
      libwebsockets_3_1
      openssl
    ] ++ lib.optional withSystemd systemd;
  
    cmakeFlags = [
      "-DWITH_THREADING=ON"
  