Fix compilation with QT_NO_STL.
Fix compilation with QT_NO_STL.

cyndis/qtgstreamer,dejunk/gstreamer,detrout/qt-gstreamer,freedesktop-unofficial-mirror/gstreamer__qt-gstreamer,detrout/qt-gstreamer,iperry/qt-gstreamer,ylatuya/qt-gstreamer,comicfans/libqtgstreamer,tswindell/qt-gstreamer,comicfans/libqtgstreamer,iperry/qt-gstreamer,GStreamer/qt-gstreamer,iperry/qt-gstreamer,ylatuya/qt-gstreamer,tswindell/qt-gstreamer,dejunk/gstreamer,shadeslayer/qtgstreamer,knuesel/qt-gstreamer,shadeslayer/qtgstreamer,detrout/qt-gstreamer,knuesel/qt-gstreamer,comicfans/libqtgstreamer,nasserGanjali/QtGStreamer,GStreamer/qt-gstreamer,nasserGanjali/QtGStreamer,dejunk/gstreamer,freedesktop-unofficial-mirror/gstreamer__qt-gstreamer,tswindell/qt-gstreamer,knuesel/qt-gstreamer,shadeslayer/qtgstreamer,nasserGanjali/QtGStreamer,GStreamer/qt-gstreamer,cyndis/qtgstreamer,ylatuya/qt-gstreamer,cyndis/qtgstreamer,freedesktop-unofficial-mirror/gstreamer__qt-gstreamer