Fix pthread's stack_addr and stack_size implementations.
Fix pthread's stack_addr and stack_size implementations.

	* lib/sched/pthread-coro.cc (coroutine_stack_addr)
	(coroutine_stack_size): Use pthread_get_stackaddr_np and
	pthread_get_stacksize_np.

aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport