However, this brings up an interesting question --
   why is "make depend" so slow on NetBSD? Maybe its my imagination, but
   I could swear that "make depend" takes many times longer on a NetBSD
   machine than on a comparable BSDI 1.1 machine.

There are many reasons that *might* be true; one of them being that we
use GCC 2.  However, before I would believe such a claim I'd have to see
actual statistics and the exact hardware configuration of both machines.