Add support for storing per output randr/vidmode emulated resolution
into the per client data.
Since we do not have a free/delete callback for the client this uses
a simple static array. The entries are tied to a specific output by the
server_output_id, with a server_output_id of 0 indicating a free slot
(0 is the "None" Wayland object id).
Note that even if we were to store this in a linked list, we would still
need the server_output_id as this is *per client* *per output*.
This is a preparation patch for adding randr/vidmode resolution
change emulation.
Reviewed-by: Olivier Fourdan <ofourdan@redhat.com>
Acked-by: Michel Dänzer <mdaenzer@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>