-tip testing found this build failure (x86 randconfig):
 drivers/built-in.o: In function `setup_rfkill':
 compal-laptop.c:(.text+0x36abe8): undefined reference to `rfkill_alloc'
 compal-laptop.c:(.text+0x36abfc): undefined reference to `rfkill_register'
 compal-laptop.c:(.text+0x36ac30): undefined reference to `rfkill_alloc'
 compal-laptop.c:(.text+0x36ac44): undefined reference to `rfkill_register'
Which can happen with CONFIG_COMPAL_LAPTOP=y but COMPAL_LAPTOP=m.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
        tristate "Compal Laptop Extras"
        depends on ACPI
        depends on BACKLIGHT_CLASS_DEVICE
+       depends on RFKILL
        ---help---
          This is a driver for laptops built by Compal: