anchor.diff:  
       services.xserver.modules =
         concatLists (catAttrs "modules" cfg.drivers) ++ [
  -        xorg.xorgserver
  +        pkgs.xorg-server
           pkgs.xf86-input-evdev
         ];
   
  
positive.code:             attrByPath [name] (
                if xorg ? ${"xf86video" + name} then {
                  modules = [ xorg.${"xf86video" + name} ];
                } else if ${"xf86-video-" + name} then {
                  modules = [ ${"xf86-video-" + name} ];
                } else null)
                knownVideoDrivers;
            in
  
negative.code:       restartIfChanged = false;
  
        environment = {
          XKB_BINDIR = "${pkgs.xkbcomp}/bin"; # Needed for the Xkb extension.
          XORG_DRI_DRIVER_PATH = "${pkgs.opengl-dummy.driverSearchPath}/lib/dri"; # !!! Depends on the driver selected at runtime.
          LD_LIBRARY_PATH =
            concatStringsSep ":" (
              [
                "${pkgs.libx11}/lib"
                "${pkgs.libxext}/lib"
                "${pkgs.opengl-dummy.driverSearchPath}/lib"
              ] ++ concatLists (catAttrs "libPath" cfg.drivers)
            );
  