Add class forward declaration to fix build on MinGW and RVCT
Add class forward declaration to fix build on MinGW and RVCT

tmcguire/qt-mobility,tmcguire/qt-mobility,enthought/qt-mobility,qtproject/qt-mobility,enthought/qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,kaltsi/qt-mobility,enthought/qt-mobility,kaltsi/qt-mobility,tmcguire/qt-mobility,KDE/android-qt-mobility,KDE/android-qt-mobility,kaltsi/qt-mobility,tmcguire/qt-mobility,KDE/android-qt-mobility,kaltsi/qt-mobility,kaltsi/qt-mobility,kaltsi/qt-mobility,enthought/qt-mobility,tmcguire/qt-mobility,enthought/qt-mobility,KDE/android-qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,enthought/qt-mobility