wayland: Plumb some X11 code

Things such as move and resize are implemented on Wayland using event
filters that handle both X11 and Wayland clients.

Having both code paths enabled results in things getting performed
twice, e.g. window actions are executed twice, first in X11Client and
the second time in WindowActionsEventFilter.

This also fixes warnings produced by KKeyServer about an unsupported
platform.