> and they rebuild, but how does it know to use the kernel configuration we
> made with MULTIPROCESSOR, and thus compile the modules with this option?
>
> Basically, can someone say exactly how we're supposed to rebuild the kernel
> modules *without* having to rebuild the whole world?! I'm actually really
> quite stumped with this one.

This is the same question I asked on netbsd-help and then current-users 
this week. (I didn't find an answer either for build.sh.)

You could try to edit the Makefile for the individual module and add the 
-D definition (maybe -DMULTIPROCESSOR) to CPPFLAGS. And run "make" there.