Building with the attached random configuration file,
drivers/built-in.o: In function `gspca_disconnect':
/home/jim/linux/drivers/media/usb/gspca/gspca.c:2190: undefined
reference to `input_unregister_device'
drivers/built-in.o: In function `gspca_input_connect':
/home/jim/linux/drivers/media/usb/gspca/gspca.c:162: undefined
reference to `input_allocate_device'
/home/jim/linux/drivers/media/usb/gspca/gspca.c:178: undefined
reference to `input_register_device'
/home/jim/linux/drivers/media/usb/gspca/gspca.c:183: undefined
reference to `input_free_device'
drivers/built-in.o: In function `gspca_dev_probe2':
/home/jim/linux/drivers/media/usb/gspca/gspca.c:2130: undefined
reference to `input_unregister_device'
drivers/built-in.o: In function `input_report_key':
/home/jim/linux/include/linux/input.h:392: undefined reference to `input_event'
drivers/built-in.o: In function `input_sync':
/home/jim/linux/include/linux/input.h:417: undefined reference to `input_event'
drivers/built-in.o: In function `input_report_key':
/home/jim/linux/include/linux/input.h:392: undefined reference to `input_event'
drivers/built-in.o: In function `input_sync':
/home/jim/linux/include/linux/input.h:417: undefined reference to `input_event'
drivers/built-in.o: In function `input_report_key':
/home/jim/linux/include/linux/input.h:392: undefined reference to `input_event'
drivers/built-in.o:/home/jim/linux/include/linux/input.h:417: more
undefined references to `input_event' follow
make: *** [vmlinux] Error 1