message: added virtual destructor for OSX
diff: @@ -33,6 +33,8 @@ public:
  unordered_map<string, unique_ptr<ParsedExpression>> default_parameters;
  public:
  + virtual ~MacroFunction() { }
  +
  void CopyProperties(MacroFunction &other);
  virtual unique_ptr<MacroFunction> Copy() = 0;
  