now that there is a fixed GAS.

	tell the compiler that per-CPU variables can be addressed
	with "addl".

	On the simulator kernel, this saves about 2776 bytes in the
	kernel image.  On a zx1 kernel, it saves about 5593 bytes.
	As per-CPU variables are used more, these savings will
	increase, of course.

	this also ensure we really do test the linker which will be
	used when building the gate DSO.

	us from building the gate DSO in a way that makes it fit in
	<= 1 page. If a fixed linker is available, we do it in this
	space-saving way now. Otherwise, we'll do it the old way
	(the gate DSO will then take up about 18KB instead of just
	~3KB).  Thanks to Roland McGrath for making this all work.