Compilation error

```
4> c:\shiboken2_minimal_build\wrap\pyfoo\mainwindow_wrapper.cpp(1378): error C2509: 'metaObject': member function not declared in 'MainWindowWrapper'
4> c:\shiboken2_minimal_build\wrap\pyfoo\mainwindow_wrapper.h(10): note: see declaration of 'MainWindowWrapper'
```