Disable QPA platform guard
Disable QPA platform guard

We use our own platform plugin for now, but Qt doesn't
recognize it. We have to disable QPA guard to allow building
with it.

Issue: #14295

iradul/phantomjs,iradul/phantomjs,iradul/phantomjs,iradul/phantomjs,iradul/phantomjs,iradul/phantomjs,iradul/phantomjs,iradul/phantomjs,iradul/phantomjs