The documentation for wayland-server.h says:
> Use of this header file is discouraged. Prefer including
> wayland-server-core.h instead, which does not include the server protocol
> header and as such only defines the library PI, excluding the deprecated API
> below.
Replacing wayland-server.h with wayland-server-core.h allows us to drop the
WL_HIDE_DEPRECATED declaration.
It doesn't make sense to keep popups opened when unmapped. We also need to do
so in wlr_xdg_popup_destroy so that popups are destroyed in the correct order.
Simon Ser