dispatch: repair the context for the cooperative root queue

The dispatch object context for the cooperative root queue was not
initialized which resulted in the pthread root queue being invalid
when initializing the root queues. This corrects the default value
for the root queue.

Author: compnerd

src/init.c

@@ -342,6 +342,7 @@ struct dispatch_queue_global_s _dispatch_root_queues[] = {
 #define _DISPATCH_COOPERATIVE_ROOT_QUEUE_ENTRY(n, flags, ...)  \
 	[_DISPATCH_ROOT_QUEUE_IDX(n, flags)] = { \
 		.do_vtable = DISPATCH_VTABLE(queue_concurrent), \
+		.do_ctxt = _dispatch_root_queue_ctxt(_DISPATCH_ROOT_QUEUE_IDX(n, flags)), \
 		.dq_priority = flags | ((flags & DISPATCH_PRIORITY_FLAG_FALLBACK) ? \
 				_dispatch_priority_make_fallback(DISPATCH_QOS_##n) : \
 				_dispatch_priority_make(DISPATCH_QOS_##n, 0)), \