Dmitry Kazakov authored Feb 11, 2019 and Halla Rempt committed Feb 12, 2019

The follwoing patches has been dropped:

1) private headers (I'm not sure it is still needed)
2) invisible panels in fullscreen mode (it looks like it works fine now)
3) windows store wrap crash (already in 5.12.1)
4) QTBUG 57299 (QTemporaryFile problem) (already in 5.12.1)