FreeBSD's getextmntent.c is only separate because it has a different
license to mnttab.c, otherwise it would go there too.
Sponsored-by: TrueNAS
Reviewed-by: Ameer Hamza <ahamza@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <rob.norris@truenas.com>
Closes#18296
