EffectWatcher only exists on X11. (cherry-picked from 826a1eb)

theme.cpp

@@ -99,10 +99,12 @@ public:
 
         if (QPixmap::defaultDepth() > 8) {
             QObject::connect(KWindowSystem::self(), SIGNAL(compositingChanged(bool)), q, SLOT(compositingChanged(bool)));
+#ifdef Q_WS_X11
             //watch for blur effect property changes as well
             effectWatcher = 0;
             effectWatcher = new EffectWatcher("_KDE_NET_WM_BLUR_BEHIND_REGION");
             QObject::connect(effectWatcher, SIGNAL(blurBehindChanged(bool)), q, SLOT(blurBehindChanged(bool)));
+#endif
         }
 
         saveTimer = new QTimer(q);