This system call is the same as fchmodat(2), with the difference
of a flags argument that can be used to pass in either
AT_SYMLINK_NOFOLLOW, or AT_EMPTY_PATH.

fchmodat2 is very similar to fchownat, the latter also supports
this flag parameter.

Signed-off-by: Philippe Michaud-Boudreault <philmb3487@proton.me>