anchor.diff:  { stdenv, fetchFromGitHub
   , meson, ninja, pkgconfig, gettext, libxslt, docbook_xsl_ns
  -, libcap, systemd, libidn2
  +, libcap, libidn2
   }:
   
   with stdenv.lib;
  
positive.code:     ++ optional stdenv.hostPlatform.isMusl "-DUSE_IDN=false";
  
    nativeBuildInputs = [ meson ninja pkgconfig gettext libxslt.bin docbook_xsl_ns ];
    buildInputs = [ libcap systemd ]
      ++ optional (!stdenv.hostPlatform.isMusl) libidn2;
  
    meta = {
  
negative.code:     sha256 = "1jhbcz75a4ij1myyyi110ma1d8d5hpm3scz9pyw7js6qym50xvh4";
    };
  
    postPatch = ''
      # Enable the systemd units even without systemd being an input. We set the
      # unitdir manually anyway.
      sed -e 's/systemd\.found()/true/g' -i meson.build
    '';
  
    mesonFlags = [
      "-DBUILD_RARPD=true"
      "-DBUILD_TRACEROUTE6=true"
  