QVariant is not a metatype in Qt < 4.7.0

It needs to be set manually
More info, see https://bugreports.qt.nokia.com/browse/QTBUG-8549

Libs/Widgets/Testing/Cpp/ctkFlatProxyModelTest.cpp

@@ -32,6 +32,10 @@
 #include "ctkModelTester.h"
 #include "ctkTest.h"
 
+#if QT_VERSION < 0x040700
+Q_DECLARE_METATYPE(QVariant)
+#endif
+
 // ----------------------------------------------------------------------------
 class ctkFlatProxyModelTester: public QObject
 {