The Linux manual page is a little misleading, and I didn't dig further into POSIX. Mea culpa.

       O_NOFOLLOW
              If pathname is a symbolic link, then the open fails.  This is a FreeBSD extension, which was added  to  Linux  in  version
              2.1.126.  Symbolic links in earlier components of the pathname will still be followed.  See also O_PATH below.

...

       The O_CLOEXEC, O_DIRECTORY, and O_NOFOLLOW flags are not specified in POSIX.1-2001, but are  specified  in  POSIX.1-2008.