portinstall breaks with -m "-j 4"

[Mark Linimon]

> BTW, I apologize for this is not at all a portupgrade issue, but an issue
> of the ports system.

It is an issue with individual ports -- actually not the "port" (e.g.
Makefile framework, pkg-*) but the individual applications (IIUC).

> Well, at least the ports system itself should not be broken able to work
> with this. With larger ports I manage to reduce build times by 40% with
> distcc and a second machine. As far as I see it the number of ports
> breaking is rather low.

Please feel free to suggest a framework (complete with regression test
framework) where the infrastructure code can "learn" which ports are safe.
I think it's going to be a harder problem than you think it is.  Note that
"appears to work" and "can be shown to work under arbitrary build
circumstances for all users" are IMHO going to be two very different
classes of problem -- and the latter will need to be solved before it
can be used on the package-building cluster.

mcl