On compositors that support compositor key repeat events, use those, for
complete robustness. Sadly no actual compositor implements these yet.
Otherwise use a timer fd/pipe to queue the repeat events and only
dispatch them after events from the compositor are handled. This means
release events from the compositor will prevent spurious repeat events.
One can, in the worst case lose some repeat events if there is a very
large interval between the start of the timer and the next poll, but
that is unavoidable and is why repeat events should come from the compositor
in the first place.
Fixes#9224
16008b950a