Update CMakeLists.txt
Update CMakeLists.txt

> 2017/04/11 20:06:42 <vc-01>          iconNameFallback.truncate(indexOfDash);
> 2017/04/11 20:06:42 <vc-01> This is because ‘truncate’ is available since Qt 5.6.
libqtxdg/libqtxdg,lxde/libqtxdg,libqtxdg/libqtxdg,luis-pereira/libqtxdg,luis-pereira/libqtxdg,lxde/libqtxdg