Using sendrec directly only results in problems. While it is not
clear whether using fs_sendrec is the best option, it is at least
an improvement.
Also remove some legacy cruft.
In some places it was assumed that PATH_MAX does not include a
terminating null character.
Increases PATH_MAX to 1024 to get in sync with NetBSD. Required some
rewriting in AVFS to keep memory usage low (the stack in use by a thread
is very small).
