Generate the C protocol files from the protocol XML files installed by
wayland-protocols, and use them to implement support for relative pointer
motions and pointer locking.
Note that at the time, the protocol is unstable and may change in the future.
Any future breaking changes will, however, fail gracefully and result in no
regressions compared to before this patch.
Since we are loading shared objects dynamically, build our own version of the
core protocol symbols, so that we in the future can include protocol
extensions.
This will be used by Wayland compositors to match the application ID and
.desktop file to the SDL window(s).
Applications can set the SDL_VIDEO_WAYLAND_WMCLASS environemnt variable
early in the process to override using the binary name as a fallback.
Note that we also support the SDL_VIDEO_X11_WMCLASS in the Wayland
backend so that if a program correctly associated the desktop file with
the window under X11, only a newer SDL would be needed for it to work
under Wayland.
https://bugzilla.libsdl.org/show_bug.cgi?id=3376
There are platforms it isn't implemented on (and currently can't be
implemented on!), and there's currently no way for an app to know this.
This shouldn't break ABI on apps that moved to a revision between 2.0.3 and
2.0.4.
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
