Fix for build failure on Ubuntu 16.04

src/Mod/Sketcher/Gui/ViewProviderSketch.cpp

@@ -1196,7 +1196,7 @@ bool ViewProviderSketch::mouseMove(const SbVec2s &cursorPos, Gui::View3DInventor
         }
         case STATUS_SKETCH_UseRubberBand: {
             // Here we must use the device-pixel-ratio to compute the correct y coordinate (#0003130)
-#if QT_VERSION >= 0x050000
+#if QT_VERSION >= 0x050600
             qreal dpr = viewer->getGLWidget()->devicePixelRatioF();
 #else
             qreal dpr = 1;