Select only the lower two and set the correct bit for directory entries. While the lower two bytes seems to behave just as on UNIX, the upper ones don't (at least on OpenBSD.)

9front uses aname "" during Tattach, at least with 9fs without special arguments, so convert it to our current representation.

`count' should be a 2-byte (16-bit) value and we're not neither accounting for it nor sending it.