Fixes a crash in SDL2 applications when using locked pointer.
SDL2 expects a wl_pointer v1 interface and doesn't provide a handler for
the wl_pointer::frame event. This results in a "listener function for
opcode 5 of wl_pointer is NULL" abort in wayland-client.
Tested on Xonotic v0.8.2 with libSDL2 v2.0.9. Xonotic needs to be ran
with "SDL_VIDEODRIVER=wayland xonotic-sdl" for SDL2 to use the wayland
backend.
Occurs on subsequent calls to
relative_pointer_manager_v1_handle_get_relative_pointer()
Steps to reproduce:
- run rootston
- run examples/relative-pointer
- switch to relative pointer more than once
Note: if done fast enough it may take more than two switches to crash.
In particular, modified public creator and destructor function names,
added a display destroy listener, safely extract user data from
resources, send correct time (in usecs) in rootston, etc.