Building with the attached random configuration file,

sn9c102_core.c:(.text+0x1bcd22): undefined reference to `usb_submit_urb'
sn9c102_core.c:(.text+0x1bcd39): undefined reference to `usb_submit_urb'
sn9c102_core.c:(.text+0x1bcda4): undefined reference to `usb_kill_urb'
sn9c102_core.c:(.text+0x1bcdcc): undefined reference to `usb_free_urb'
sn9c102_core.c:(.text+0x1bcddd): undefined reference to `usb_free_urb'
drivers/built-in.o: In function `sn9c102_read_reg':
(.text+0x1bceb2): undefined reference to `usb_control_msg'
drivers/built-in.o: In function `sn9c102_usb_probe':
sn9c102_core.c:(.text+0x1bd155): undefined reference to `usb_get_dev'
drivers/built-in.o: In function `sn9c102_i2c_try_raw_read':
(.text+0x1bd262): undefined reference to `usb_control_msg'
drivers/built-in.o: In function `sn9c102_i2c_try_raw_read':
(.text+0x1bd2ee): undefined reference to `usb_control_msg'
drivers/built-in.o: In function `sn9c102_i2c_try_raw_read':
(.text+0x1bd340): undefined reference to `usb_control_msg'
drivers/built-in.o: In function `sn9c102_i2c_try_raw_write':
(.text+0x1bd488): undefined reference to `usb_control_msg'
drivers/built-in.o: In function `sn9c102_usb_driver_init':
sn9c102_core.c:(.init.text+0xc6e9): undefined reference to `usb_register_driver'
drivers/built-in.o: In function `sn9c102_usb_driver_exit':
sn9c102_core.c:(.exit.text+0x278b): undefined reference to `usb_deregister'
make: *** [vmlinux] Error 1