0.8.2.15:

0.8.2.15:
	Add all remaining required (*ptui*) specialized arrays:
	... (UNSIGNED-BYTE {7,15,29,31});
	While we're at it, make the cross-compiling dumper more likely
		to complain if we give it weird array types; we assume
		(unsigned-byte {8,16,32}) are generally supported by
		implementations.
	Also make (ARRAY NIL) dumpable in the target compiler.
	Tested building from cmucl, openmcl, old and new sbcl on x86 and
		ppc.  Will need confirmation from other architectures.