A week or two ago I sent mail with a patch/makefile for locks and parallel
builds. I was asked to put it all into bsd.port.mk, so here it is.
If you set either of the parallel flags, I strongly suggest you use BATCH.
If a config screen pops up during a build where 4 dependencies are running
at a time, you will not be too happy. You can set NO_LOCKS to ignore all
the locks that have been added, but parallel dependencies and fetching won't
work without them (I don't know why you wouldn't want them anyway...). You
can also set BUILD_TRACKER to get some tagged output to see which ports are
building when, but this breaks certain messages.
I also plan on adding a list of relevant targets so that when running
targets what don't need the initial lock, there aren't duplicate warnings.