There is no ND_NO_FREE_PNBUF macro. Should be NDF_NO_FREE_PNBUF. Attached
patch [diff.0.namei.9] corrects this mistake in namei.9.

How-To-Repeat: There is no ND_NO_FREE_PNBUF:

% man namei | grep ND_
                      buffer intact, the ND_NO_FREE_PNBUF flag can be passed
% find /usr/include -exec grep -H ND_NO_FREE_PNBUF '{}' \;
%

There is NDF_NO_FREE_PNBUF:
% grep NDF_NO_FREE_PNBUF /usr/include/sys/namei.h
#define NDF_NO_FREE_PNBUF       0x00000020
#define NDF_ONLY_PNBUF          (~NDF_NO_FREE_PNBUF)