* remote.c (remote_notice_new_inferior): Use ptid_is_pid. Check

	* remote.c (remote_notice_new_inferior): Use ptid_is_pid.  Check
	if the thread's ptid without a thread id field is in the list
	before calling thread_change_ptid.
	(extended_remote_attach_1): In non-stop mode, do not rely on
	querying the current thread, instead, query the thread list, and
	select the first thread of the process.
	* gdbthread.h (first_thread_of_process): Declare.
	* thread.c (first_thread_of_process): Define.