Fix a compilation warning reported by the nightlies

git-svn-id: http://root.cern.ch/svn/root/trunk@36079 27541ba8-7e3a-0410-8455-c3a389f83636

graf2d/qt/src/TQtMarker.cxx

@@ -63,7 +63,7 @@ void TQtMarker::SetMarkerAttributes(const TAttMarker& markerAttributes)
    // Map Qt marker  attributes to ROOT TAttMaker parameters
    fCindex     = markerAttributes.GetMarkerColor();
    SetPenAttributes(markerAttributes.GetMarkerStyle());
-   fNumNode    = markerAttributes.GetMarkerSize();
+   fNumNode    = Int_t(markerAttributes.GetMarkerSize());
 }
 
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