message: Make Structure::mStructureId protected instead of private
diff: @@ -166,6 +166,9 @@ protected:
  void resourcesIn(const StorableResources& resources) { mResourcesInput = resources; }
  +protected:
  + StructureID mStructureId{ StructureID::SID_NONE };
  +
  private:
  Structure() = delete;
  @@ -184,8 +187,6 @@ private:
  int mMaxAge = 0; /**< Maximum number of turns the Structure can remain in good repair. */
  int mEnergyRequirement = 0;
  - StructureID mStructureId{ StructureID::SID_NONE };
  -
  StructureState mStructureState = StructureState::UnderConstruction; /**< State the structure is in. */
  StructureClass mStructureClass; /**< Indicates the Structure's Type. */
  ConnectorDir mConnectorDirection = ConnectorDir::CONNECTOR_INTERSECTION; /**< Directions available for connections. */
  