These can be used to pass extra options to the mdmfs(8) utility, to customize the finer details of the md file system creation (i.e. to turn on/off softupdates, to specify a default owner for md filesystem, etc). Use these two new flags to mount tmpmfs and varmfs without softupdates, since it doesn't make much sense to use SU on malloc-backed file systems. Reviewed by: mtm Inspired by: J. D. Bronson, jbronson at wixb dot com