In addition to referencing buffer memory by index, add support to referencing it using dmabuf file descriptors. This will be used to reference buffer memory allocated outside of libcamera and import it. The dmabuf file descriptors are stored in an array in the Buffer class, and a new Stream::createBuffer() overload is added to construct a buffer from dmabuf file descriptor. Signed-off-by: Jacopo Mondi <jacopo@jmondi.org> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>