This callback allowed compositors to customize the EGL config used by
the renderer. However with renderer v6 EGL configs aren't used anymore.
Instead, buffers are allocated via GBM and GL FBOs are rendered to. So
customizing the EGL config is a no-op.
Expose the remote wl_display, wl_surface and wl_seat used by the Wayland
backend.
This allows compositors to customize the Wayland backend and to have
more freedom. For instance a compositor might want to handle clipboard
and drag-and-drop from the remote Wayland compositor. Another compositor
might want to setup pointer constraints.
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.
Compositors now have more control over how the backend creates its
renderer. Currently all backends create an EGL/GLES2 renderer, so
the necessary attributes for creating the context are passed to a
user-provided callback function. It is responsible for initializing
provided wlr_egl and to return a renderer. On fail, return 0.
Fixes#987
Add a remote display name argument to wlr_wl_backend_create.
If NULL is passed to the wayland backend at all times, creating a
wayland backend *after* the compositor was started up, would require
changing the WAYLAND_DISPLAY environment variable.
