Nesting namespace names in a single namespace declaration is a C++17 feature. As libcamera depends on C++11 only, nest two separate namespace declarations instead. Reported-by: Shik Chen <shik@google.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>