sapi: Return wait status in async_wait_queue_empty.

dlls/sapi/async.c

@@ -171,8 +171,8 @@ HRESULT async_queue_task(struct async_queue *queue, struct async_task *task)
     return S_OK;
 }
 
-void async_wait_queue_empty(struct async_queue *queue, DWORD timeout)
+HRESULT async_wait_queue_empty(struct async_queue *queue, DWORD timeout)
 {
-    if (!queue->init) return;
-    WaitForSingleObject(queue->empty, timeout);
+    if (!queue->init) return WAIT_OBJECT_0;
+    return WaitForSingleObject(queue->empty, timeout);
 }

dlls/sapi/sapi_private.h

@@ -42,7 +42,7 @@ HRESULT async_start_queue(struct async_queue *queue);
 void async_empty_queue(struct async_queue *queue);
 void async_cancel_queue(struct async_queue *queue);
 HRESULT async_queue_task(struct async_queue *queue, struct async_task *task);
-void async_wait_queue_empty(struct async_queue *queue, DWORD timeout);
+HRESULT async_wait_queue_empty(struct async_queue *queue, DWORD timeout);
 
 HRESULT data_key_create( IUnknown *outer, REFIID iid, void **obj );
 HRESULT file_stream_create( IUnknown *outer, REFIID iid, void **obj );