anchor.diff:    ];
   
     nativeBuildInputs = [ pkg-config meson ninja ]
  -    ++ optionals documentationSupport [ doxygen graphviz sphinx-build ];
  +    ++ lib.optionals documentationSupport [ doxygen graphviz sphinx-build ];
   
     buildInputs = [
       libevdev
  
positive.code:   else null;
  in
  
  with lib;
  stdenv.mkDerivation rec {
    pname = "libinput";
    version = "1.16.4";
  
negative.code: { lib, stdenv, fetchFromGitLab, pkg-config, meson, ninja
  , libevdev, mtdev, udev, libwacom
  , documentationSupport ? false, doxygen, graphviz # Documentation
  , eventGUISupport ? false, cairo, glib, gtk3 # GUI event viewer support
  , testsSupport ? false, check, valgrind, python3
  }:
  
  let
    mkFlag = optSet: flag: "-D${flag}=${lib.boolToString optSet}";
  