Add a patch for Qt 5.14.2 support
The system of having headers for every possible Qt version is insane and causes problems with almost every our Qt transition. Also, the sources only use 10 headers out of 24.
If I were upstream, I would use a single copy of headers with some #if checks for Qt version where needed. Or even better, work with upstream Qt developers to make the API they need official.
Anyway, I added a patch similar to the existing one to add Qt 5.14.2 headers.
Closes: #960953.
Cc @byang