error: ‘constexpr’ needed for in-class initialization of static data member ‘const double sba::Con2d
error:‘constexpr’neededforin-classinitializationofstaticdatamember‘constdoublesba::Con2dP2::qScale’ofnon-integraltype[-fpermissive]编译ROS的slam_karto时出现的错误:/opt/ros/kinetic/include/sparse_bundle_adjustm