- During makeplist, emit only empty directories inside prefix and
  directories outside prefix
- Whitelisting orphan directories not starting with / is no longer necessary
- Adjust missing directories check to use a list of all directories instead
  of the dirs from make-plist

Differential Revision:	https://reviews.freebsd.org/D1101
Reviewed by:	bapt
With hat:	portmgr


git-svn-id: svn+ssh://svn.freebsd.org/ports/head@372177 35697150-7ecd-e111-bb59-0022644237b5