anchor.diff:  , meson
   , ninja
   , libGL
  -, libglvnd
  +, libglvnd ? null
   , makeWrapper
   , pkg-config
  -, wayland
  -, libxcb
  -, libX11
   , python3
  +, x11Support ? true, libxcb ? null, libX11 ? null
  +, waylandSupport ? true, wayland ? null
  +, useGbm ? true, mesa ? null, libudev ? null
   }:
  +
  +assert x11Support -> (libxcb != null && libX11 != null);
  +assert waylandSupport -> wayland != null;
  +assert useGbm -> (mesa != null && libudev != null);
  +assert with stdenv.hostPlatform; isUnix && !isDarwin -> libglvnd != null;
   
   stdenv.mkDerivation rec {
     pname = "waffle";
  
positive.code:     makeWrapper
      pkg-config
      python3
    ];
  
    mesonFlags = [
      "-Dgbm=disabled"
    ];
  
    postInstall = ''
  
negative.code: 
    buildInputs = [
      libGL
    ] ++ stdenv.lib.optionals (with stdenv.hostPlatform; isUnix && !isDarwin) [
      libglvnd
    ] ++ stdenv.lib.optionals x11Support [
      libX11
      libxcb
    ] ++ stdenv.lib.optionals waylandSupport [
      wayland
    ] ++ stdenv.lib.optionals useGbm [
      mesa
      libudev
    ];
  
    nativeBuildInputs = [
  