MacVFS -> mac-sys-utils:  Move/rename rom_size()
rom-checksum:  Account for other Mac Classic ROMs
mac-sys-utils -> async-wakeup:  Move to a new unit
async-wakeup:  Make 32-bit clean

Using the qLink's high byte as a lock byte is fine (potentially) for the
68000 (and 68010, though that doesn't come into play in Mac OS), but for
68020 and later, it's incompatible with 32-bit mode.  Instead, just call
OTCompareAndSwapPtr() like PPC does (which is implemented with CAS here,
which isn't supported on the 68000 -- which is why TAS is even needed at
all).