For supporting output layout, compositors need the ability to manually set the
'weston_output' by 'weston_output_move'.
Signed-off-by: sichem <sichem.zh@gmail.com>
Introduce a new private header file that only internal backends are
allowed to use. Starts by migrating functions that operate on the
'struct weston_head'.
Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
