Get rid of using private Qt logic

[leha-bot]

It could improve the infrastructure and reduce build complexity.

[ForNeVeR]

I'd recommend to try build the project without Qt private modules and check for the build errors.

[leha-bot]

https://github.com/procxx/kepka/search?utf8=%E2%9C%93&q=%22include+private%22

(thanks for @xvitaly for hint)

[Randl]

https://github.com/Randl/tdesktop/commit/7554b45080e93e5860ee4618ce9dfc2eac298ab7

List of headers:

• qcoreapplication_p.h
• qcssparser_p.h
• qfixed_p.h
• qfontengine_p.h
• qfont_p.h
• qfragmentmap_p.h
• qglobal_p.h
• qguiapplication_p.h
• qharfbuzz_p.h
• qobject_p.h
• qplatformnativeinterface.h
• qshortcutmap_p.h
• qtextdocument_p.h
• qtextengine_p.h
• qtextformat_p.h
• qtguiglobal_p.h
• qthread_p.h
• qtools_p.h
• qunicodetools_p.h
• qwindowsysteminterface.h
• qwindowsysteminterface_p.h