A month or two ago I set MAKE_JOBS=4 in mk.conf on my notebook (Core
Duo).  I have rebuilt packages with pkg_rolling-replace a number of
times, and it seems that each time I do I find a few packages that fail.
I've been committing MAKE_JOBS_SAFE=no, sometimes with a comment about
why.

I haven't tried to fix the offending packages, because that would take
more time than I have, and I think it's incremental progress to just
mark them as unsafe.

Has anyone run bulk builds with MAKE_JOBS=4 on a dual-processor, or some
higher values?   I would expect that there would be a lot of failures,
but also that we're getting to the point where it's almost reasonable
for people to turn on MAKE_JOBS.