I think I figured out the Arch build problem.  GDB tells me that
an off_t is on a 4 byte boundary instead of an 8 byte boundary,
thus causing a bus error.  I have alerted Tom Lord to the problem,
or at least my suspicions.  I'm not sure how long it will take him
to fix it, and I'm not sure if I have enough clue.

I suspect it will work just fine on my pc532 if I try it there, or
on an i386 machine, or anything else that only needs long alignment
on off_t types.

Jon