[Mesa-dev] anv/radv: WSI sharing code

[Dave Airlie]

This series builds on top of the previous sharing patches I sent.

The aim here is to share the X11 and wayland WSI code between
the two vulkan drivers so we have a consistent implementation and
one place to fix bugs.

The series modifies the anv code in place until it's suitable
for sharing, then it moves it to shared directory, and ports
radv to use it.

The final code leaves the WSI APIs in the drivers, but they
call directly into the shared code once they shed their driver
specific structs, and pick a pAllocator.

Dave.