Upstream homepage
   http://www.xavierdidelot.xtreemhost.com/clonalframe.htm
says:

  For the GUI of ClonalFrame, please download the Windows version 1.1
  below. Please note that this GUI is no longer supported ...

So in principle we do not need to link against Qt5 libs at all but qmake
somehow tweaks this in.  If somebody knows how to prevent this it would
be nice to apply.
