You've never built a kernel before, right? In order for make dep to work, you need to do a make config. Since you don't want to change *anything* (since you're not building a kernel, just faking up what Bruce built for you in the original install disks) I think just doing a "make oldconfig" will work.
It turns out that this has nothing to do with the autoconf package; the linux kernel uses some automatic configuration, and steals the name, but it isn't actually using GNU-Autoconf(TM) :-) (A further hint to this is that the earliest version of the autoconf package is only a few months old -- I built it -- yet people have been building kernels, like this one, for years :-)
