Looks like you have to have a pci_domain just adding a northbridge didn't fix it.
So now I'm at
chip northbridge/intel/440bx device pci_domain 0 on end chip cpu/intel/socket_PGA370 end end
I noticed that I also have 4 irq slots specified. So pci slots with no pci_domain. Perhaps thats what was tripping up buildtarget?
Does IRQ_SLOT_COUNT have to match how many actual slots are on the MB or just the number of pci devices in total?