Problems in KWayland causes by API and ABI compatibility promises

[David Edmundson]

There's another problem we're going to hit with kwayland at some point
in the future.

KWayland specifies the protocol version.
This means, according to framework policies we might have a released
kwin which suddenly gets a new protocol version of something being
announced.

I just had a near miss with XdgOutputV1(version2) which luckily we
were able to easily guard. Had the spec claimed that in version2
sending xdg_output.name was mandatory we would have been completely
screwed.

I'm seeing quite a few version bumps that change semantics coming up
in wayland-protocols for other things.

We either need the protocol version to be set from the compositor
instead of kwayland or for kwayland to be more explicitly tied to
kwin.

David