Support ext-data-control wayland-protocol (replacing wlr-data-control)

[Conan-Kudo]

wlr-data-control-unstable-v1 has been superseded with ext-data-control-v1 in wayland-protocols, and will be included in wayland-protocols v1.39.

Please add support for ext-data-control so that this works with compositors that only support the standardized extension.

[bugaevc]

Thanks for bringing this to my attention. We should certainly add support for it.

That being said, I am quite disappointed that this protocol was standardized without as much as cc'ing the [one of the] primary client-side user[s] of the wlr-data-control protocol. (Nor, from looking at the MR, were other clients' developers notified?). Don't you need (multiple?) client-side implementation(s) for a protocol to be accepted? Aren't you interested in the feedback we might have?

And I do have suggestions indeed, ones that I gave up on getting past the wlroots folks. A new neutral protocol under the Wayland governance could have been a great time to bring them up again.

[Conan-Kudo]

I was unaware of clients to reach out to (I had, perhaps wrongfully assumed that the w-p MR alone would let stakeholders know it was ongoing). I started doing this after it landed as I'm working through the backlog of custom protocols used by KDE. Sorry about that.