0.7.13.21:

0.7.13.21:
	The (ARRAY NIL) has landed.
	... implement a SIMPLE-ARRAY-NIL primitive type, including in
		garbage collection and (ROOM) logic;
	... adjust implementation of array creation and reference to
		deal with arrays that can't contain anything;
	... (HAIRY-)DATA-VECTOR-REF are can no longer be FLUSHABLE;
	Enjoy!