Package virtualbox-guest-utils missing vboxwl helper for Wayland guests

Since version 7.1.x VirtualBox not only provides better support for Wayland hosts but also for Wayland guests. For that the VBoxClient-all script (or 98vboxadd-xclient in the source distribution) has a new test to check whether the X11 or Wayland version of VBoxClient should be started. This test requires a helper named vboxwl that currently isn't built and/or packaged with virtualbox-guest-utils, causing the script to always assume X11 even when running under Wayland.

According to the Makefile.kmk, VBOX_WITH_WAYLAND_ADDITIONS needs to be defined in order to build VBoxClient with Wayland support, along with vboxwl.