libc/nftw: Bring in some fixes from FreeBSD.

* Silently skip directories causing loops (instead of erroring with ELOOP).

* Refresh OpenBSD CVS IDs.

* Don't check maxfds against OPEN_MAX.
kernel/hammer2: Remove two unused malloc types, W_BIOQUEUE and W_MTX.
make upgrade: Do no longer remove multibyte.3
make upgrade: Clean up after the "locale megapatch".