QX11PixmapData::transformed does not set serialNumber

QX11PixmapData::transformed does not initialize the new QX11PixmapData object with a serial number.

— a/src/gui/image/qpixmap_x11.cpp
+++ b/src/gui/image/qpixmap_x11.cpp
@@ -1932,6 +1932,8 @@ QPixmap QX11PixmapData::transformed(const QTransform &transform,
x11Data->hd = (Qt::HANDLE)XCreatePixmap(X11->display,
RootWindow(X11->display, xinfo.screen()),
w, h, d);
+ x11Data->setSerialNumber(++qt_pixmap_serial);
+
#ifndef QT_NO_XRENDER
if (X11->use_xrender) {
XRenderPictFormat *format = x11Data->d == 32