Use a full path to the target for make rules which create symlinks @,
machine and ${MACHINE_CPUARCH}. Otherwise the presence of a file named
"x86" or "x86.c" in the make path can cause problems.

Submitted by:	lwhsu (original version)
MFC after:	1 month
Use an empty ranges statement for the bus, because all the children on the
bus have their register properties declared as full physical addresses,
not offsets from a base range for the bus.