anchor.diff: -{ lib, stdenv, fetchurl, pkgconfig
  +{ lib, stdenv, fetchurl, meson, pkgconfig, ninja
   , libffi, libxml2, wayland
   , expat ? null # Build wayland-scanner (currently cannot be disabled as of 1.7.0)
   }:
  
positive.code:   buildInputs = [ libffi /* docbook_xsl doxygen graphviz libxslt xmlto */ expat libxml2 ];
  
    meta = {
      description = "Reference implementation of the wayland protocol";
      homepage    = https://wayland.freedesktop.org/;
      license     = lib.licenses.mit;
      platforms   = lib.platforms.linux;
      maintainers = with lib.maintainers; [ codyopel ];
    };
  
    passthru.version = version;
  
negative.code: 
  stdenv.mkDerivation rec {
    pname = "wayland";
    version = "1.18.0";
  
    src = fetchurl {
      url = "https://wayland.freedesktop.org/releases/${pname}-${version}.tar.xz";
      sha256 = "0k995rn96xkplrapz5k648j651wc43kq817xk1x8280h16gsfxa6";
    };
  
    separateDebugInfo = true;
  
    mesonFlags = [ "-Ddocumentation=false" ];
  
    nativeBuildInputs = [
      meson pkgconfig ninja
    ] ++ lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [
      # for wayland-scanner during build
      wayland
  