this for 'initiator id'- this is a stopgap until a sparse map is
added.
Make compat defines for offset format (FreeBSD 5 or less).
Add no-asyncio flag. There's some breakage with ASYNC I/O that every
now and then drops us into an infinite loop. This also then does
a fallback to no-asyncio if the AIO option isn't loaded/compiled into
the kernel.
A number of other chanes to try and track some breakage.
cd6dedfc61