Compile when -no-rtti is specified as a configure option

After discussing with Marko who did the original backport of the
ShaderEffect to Qt 4.7 it was agreed that this is the correct thing to
do in this case.

Merge-request: 2713
Task-number: QTBUG-22419
Reviewed-by: Marko Niemelä

Author: Andy Shaw

src/imports/shaders/shadereffect.cpp

@@ -61,6 +61,7 @@ ShaderEffect::~ShaderEffect()
 
 void ShaderEffect::prepareBufferedDraw(QPainter *painter)
 {
+#ifndef QT_NO_DYNAMIC_CAST
     // This workaround needed because QGraphicsEffect seems to always utilize default painters worldtransform
     // instead of the active painters worldtransform.
     const ShaderEffectBuffer *effectBuffer = dynamic_cast<ShaderEffectBuffer*> (painter->device());
@@ -70,6 +71,9 @@ void ShaderEffect::prepareBufferedDraw(QPainter *painter)
     } else {
         savedWorldTransform = painter->worldTransform();
     }
+#else
+    Q_UNUSED(painter);
+#endif
 }
 
 void ShaderEffect::draw (QPainter *painter)