If LIBCAMERA_BASE_PRIVATE is ever exposed on the libcamera public dependencies,
then the private.h header protection will be circumvented.
Provide a test which will fail (at compile time) if the LIBCAMERA_BASE_PRIVATE
define ever leaks to the public dependencies.
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
