[Development] Orphan modules

[Sune Vuorela]

On 2018-09-12, Gatis Paeglis <Gatis.Paeglis at qt.io> wrote:
> +1 for deprecating qtx11extras as well and moving the code closer to actual plugin. It is frustrating to have all that boilerplate code for 1 header file - qx11info_x11.h

I think it makes sense to have qtx11extras. A stable api and abi that
X11 users can rely on.

I see the only alternative is to provide stable apis in QPA and friends
instead. But that has so far been refused.

/Sune