patch by Patrick Mihelich: use empty struct + anonymous namespace for NoChange
patch by Patrick Mihelich: use empty struct + anonymous namespace for NoChange

ROCmSoftwarePlatform/hipeigen,pasuka/eigen,toastedcrumpets/eigen,TSC21/Eigen,ritsu1228/eigen,ROCmSoftwarePlatform/hipeigen,pasuka/eigen,pasuka/eigen,ritsu1228/eigen,toastedcrumpets/eigen,toastedcrumpets/eigen,TSC21/Eigen,Zefz/eigen,ritsu1228/eigen,ritsu1228/eigen,TSC21/Eigen,pasuka/eigen,ritsu1228/eigen,Zefz/eigen,TSC21/Eigen,pasuka/eigen,Zefz/eigen,ROCmSoftwarePlatform/hipeigen,Zefz/eigen,toastedcrumpets/eigen,ROCmSoftwarePlatform/hipeigen