message: Bugfix for linker error in PointInCellTraits static member
  Introduced as a way of fixing a 'multiply-defined' linker error in a recent PR.
  The resolution here converts the static member to an enum.
diff: @@ -77,7 +77,7 @@ public:
  typedef int IndexType;
  /*! Special value to indicate an unsuccessful query */
  - static constexpr IndexType NO_CELL = -1;
  + enum Values : IndexType { NO_CELL = -1 };
  };
  namespace detail
  