Add struct weston_drm_format, which contains a DRM format and a list of
modifiers. The patch also adds struct weston_drm_format_array and some
helper functions to handle these two new structs: init/fini, find
elements, add elements, etc.
This will be useful in the next commits in which we add support to
dmabuf-hints. It also allows a cleanup in the DRM-backend, where we
currently have a similar struct in drm_plane but with no helper
functions, so the code to handle it is scattered throughout the
functions and there is a lot of repetition.
This patch is based on previous work of Scott Anderson (@ascent).
Signed-off-by: Scott Anderson <scott.anderson@collabora.com>
Signed-off-by: Leandro Ribeiro <leandro.ribeiro@collabora.com>
