The IPA module signing mechanism relies on openssl to generate keys and sign the module. If openssl is not found on the system, the build will fail. Make the dependency optional by detecting openssl, and skip generation of signatures if openssl isn't found. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>