>>> Don't you ever build for example emacs and xmms at the same time, given
>>> that you already have X and possibly other basic packages installed?
>>
>> no. :)
>>
>> So you basically want to work around the bug of make -jX not working
>> properly... hard to say anything against that.
>
> Isn't what you are thinking of here "the problem that several packages
> have not been prepared for parallel build using 'make -jX' with X>1"?
>
> If that's the case, then it's not so much a case of a bug in make, but
> rather a problem with insufficiently specified dependencies in the
> packages' Makefiles.  Since we're talking about third-party software
> typically not exposed to parallel builds, I'd say it would be
> difficult at best to fix all of pkgsrc's package Makefiles to play
> nice with "make -jX", so following that avenue of attack to making
> good use for more than one CPU is going to be an uphill battle at
> best.
>
> Going into whishlist mode: Making use of multiple CPUs on a single
> physical machine could be the relatively simple first step in making
> it possible to spread package builds across multiple machines in order
> to speed up package builds for a given architecture...  Clustered bulk
> builds, anyone?

The problem is not with packages.  It is either bmake, or pkgsrc 
Makefiles, or both.

Speaking from experience :)
Adam