They're no longer needed since we don't expose any atoms in the
published API anymore. As a result, we don't need to support external
atom implementations either. Result!
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
And use it consistently everywhere, including with a special long-safe
internal keycode type, to ease the transition to large keycodes.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>