Building with the attached random configuration file,
drivers/built-in.o: In function `v4l2_flash_open':
v4l2-flash-led-class.c:(.text+0x27f495): undefined reference to
`v4l2_fh_is_singular'
drivers/built-in.o: In function `v4l2_flash_init':
(.text+0x27fe35): undefined reference to `v4l2_subdev_init'
drivers/built-in.o: In function `v4l2_flash_init':
(.text+0x280554): undefined reference to `v4l2_ctrl_handler_init_class'
drivers/built-in.o: In function `v4l2_flash_init':
(.text+0x2805c0): undefined reference to `v4l2_ctrl_new_std'
drivers/built-in.o: In function `v4l2_flash_init':
(.text+0x2806a3): undefined reference to `v4l2_ctrl_new_std_menu'
drivers/built-in.o: In function `v4l2_flash_init':
(.text+0x2806f3): undefined reference to `v4l2_ctrl_handler_setup'
drivers/built-in.o: In function `v4l2_flash_init':
(.text+0x280732): undefined reference to `v4l2_async_register_subdev'
drivers/built-in.o: In function `v4l2_flash_init':
(.text+0x280785): undefined reference to `v4l2_ctrl_handler_free'
drivers/built-in.o: In function `v4l2_flash_init':
(.text+0x2807a9): undefined reference to `v4l2_ctrl_handler_free'
drivers/built-in.o: In function `v4l2_flash_release':
(.text+0x280815): undefined reference to `v4l2_async_unregister_subdev'
drivers/built-in.o: In function `v4l2_flash_release':
(.text+0x28084a): undefined reference to `v4l2_ctrl_handler_free'
drivers/built-in.o: In function `v4l2_flash_close':
v4l2-flash-led-class.c:(.text+0x2808c5): undefined reference to
`v4l2_fh_is_singular'
v4l2-flash-led-class.c:(.text+0x28093b): undefined reference to
`__v4l2_ctrl_s_ctrl'
drivers/built-in.o: In function `board_staging_register_clock':
(.init.text+0x10ba1): undefined reference to `clk_add_alias'
drivers/built-in.o:(.rodata+0xe3110): undefined reference to
`v4l2_subdev_queryctrl'
drivers/built-in.o:(.rodata+0xe3140): undefined reference to
`v4l2_subdev_querymenu'