Make a whole bunch of PCB variables ints rather than shorts. There appear
to be no ill effects, and so far as Iknow none of the variables in
question depend on 16-bit wraparound behavior. (The sizes are in
many cases relics from when a PCB had to fit inside a 128-byte mbuf. PCBs
are no longer stored in that way, and the old structure would not have
fit, either.)