linux: Implement F_DUPFD_QUERY fcntl with kcmp(2) KCMP_FILE
Signed-off-by: Ricardo Branco <rbranco@suse.de>
Reviewed by: kib
Pull Request: https://github.com/freebsd/freebsd-src/pull/1920
(cherry picked from commit fe21dbf70aa8c6dfd2010f30dd2d09f7b743e77d)