This interface is getting replaced, so relocating it to the deprecated wrapper package before working on its replacement.
Signed-off-by: Ophestra <cat@gensokyo.uk>
Note: wl_registry_add_listener is undocumented everywhere. Its implementation calls wl_proxy_add_listener which returns 0 on success or -1 on failure.
Signed-off-by: Ophestra <cat@gensokyo.uk>
