clients: add simple-v4l-dmabuf client

This client opens a V4L2 device, usually exposed as /dev/videoN, and
retrieves its frames as dmabuf for later import into the compositor.

It supports both single- and multi-planar devices, and any format
exposed by the V4L2 device the Wayland compositor accepts.

This client never changes the v4l2 settings, use `v4l2-ctl -c` if you
want to change those.

Signed-off-by: Emmanuel Gil Peyrot <emmanuel.peyrot@collabora.com>
Acked-by: Derek Foreman <derekf@osg.samsung.com>
Tested-by: Derek Foreman <derekf@osg.samsung.com>

Maniphest Tasks: T90

Differential Revision: https://phabricator.freedesktop.org/D339
4 files changed