* thread-db.c (ALWAYS_UPDATE_THREAD_LIST): Define to be 0.

	* thread-db.c (ALWAYS_UPDATE_THREAD_LIST): Define to be 0.
	(handle_thread_db_event): Update thread list upon receipt of
	TD_CREATE or TD_DEATH events.
	(thread_db_check_child_state): Potentially disable, depending upon
	value of ALWAYS_UPDATE_THREAD_LIST, the thread list update.
	(thread_db_check_child_state): Update thread list for signal based
	event model too.