BUG: Patch from Clinton to restore proper QT3_SUPPORT macro definition.

Modules/UseQt4.cmake

@@ -33,6 +33,7 @@ ENDMACRO(QT_MODULE_SETUP)
 
 IF (QT_USE_QT3SUPPORT)
   QT_MODULE_SETUP(3SUPPORT)
+  ADD_DEFINITIONS(-DQT3_SUPPORT)
 ENDIF (QT_USE_QT3SUPPORT)
 
 IF (QT_USE_QTOPENGL)