Add a define in both the source and Makefile for enabling logging of z80 instruction address/cycle counts. Fix Z80 in/out instructions to eliminate assumptions about which registers are stored in native regs. Fix read_16 to not corrupt the low byte when the read has to call into a C function.

    dc.l $0, start
start:
	moveq #36, d0
	bsr fib
	illegal
fib:
	cmp.l #2, d0
	blt base
	subq.l #1, d0
	move.l d0, -(a7)
	bsr fib
	move.l (a7), d1
	exg d0, d1
	move.l d1, (a7)
	subq.l #1, d0
	bsr fib
	move.l (a7)+, d1
	add.l d1, d0
	rts
base:
	moveq #1, d0
	rts