I'm seeing:
 `acpiphp_glue_exit' referenced in section `.init.text' of
drivers/built-in.o: defined in discarded section `.exit.text' of
drivers/built-in.o

when trying to compile an IA64 kernel with PCI hotplug enabled.

I suggest this patch:
Signed-off-by: Peter Chubb <peterc@gelato.unsw.edu.au>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>