[Windows] Clang backend crashes when developing qpa backend

Project to use has been the winrt qpa plugin.
For setup you will need a checkout of Qt and MSVC2015. If you have a WinRT version installed from the Qt installer, it should be sufficient to open up the winrt.pro in qtbase/src/plugins/platforms/winrt and then try to do a couple of completions. QWinRTScreen has a couple of members, which point deeply into the Windows headers.