Later, a similar inproc sync as the queue will be created for user APC alerts and sent on thread init as well, saving us the need to special case those in the get_inproc_sync request and in the cache.
-- v2: ntdll: Notify wineserver when waiting on inproc queue. server: Create an inproc sync for message queue signaling. win32u: Move server queue handle to ntuser_thread_info. ntdll: Introduce a helper to wait on an server-side sync object. ntdll: Check inproc sync signal rights in signal and wait. server: Move signal access checks outside of the objects.