2.4.18-rmk3 fails to build on the EBSA285 if there is no video stuff
enabled with a missing symbol.  For me the linker lied and told me it
was in irq.c but it was actually in the previous file in the link,
mach-footbridge/arch.c ; the symbol is screen_info which is what the
ORIG_* macros use.

Note I haven't yet tested this booting, just building.