message: In class LinearForm, initialize 'extern_lfs' in the default
  constructor.
diff: @@ -79,7 +79,7 @@ public:
  /** The associated FiniteElementSpace can be set later using one of the
  methods: Update(FiniteElementSpace *) or
  Update(FiniteElementSpace *, Vector &, int). */
  - LinearForm() { fes = NULL; }
  + LinearForm() { fes = NULL; extern_lfs = 0; }
  /// Copy assignment. Only the data of the base class Vector is copied.
  /** It is assumed that this object and @a rhs use FiniteElementSpace%s that
  