Weston's dmabuf implementation continues to be modular enough that we can
pull it in with minimal change.
This updates us to version 3 of the protocol - required by recent mesa to
use dmabuf buffers instead of wl_drm ones.
Currently only contains stubs for format query.
This adds compositor handling of DMABuf buffers. DMAbuf capabilities
are advertised for the drm back-ends, and DMAbuf buffers are handled
as native surfaces.
Derek Foreman
Mike Blumenkrantz