lock port for concurrent builds
lockname [comment ...]
portlock creates a lock named
lockname using open(2).
If the lock is already held, it will display one single wait message on
stderr, sleep and retry until satisfaction.
If necessary, creates the lock directory, using
-m mode as a mode argument or
the default if that option is not specified, and
group as the group owner if that option is
This implements a locking mechanism for ports building, see
‘LOCK INFRASTRUCTURE’ in
ports(7) for details. See also
dpb(1) for a complementary lock
infrastructure when using dpb.