[Qt-creator] Increasing requirements to Qt 5.11 for Qt Creator master/4.10

[Eike Ziller]

The following patch increases the requirement for building Qt Creator to Qt 5.11:

https://codereview.qt-project.org/253333

Qt 5.12, the new LTS is released, and until Qt Creator 4.10, Qt 5.13 will be released as well. We accumulated some version ifdefs, also want to replace some API that is deprecated in Qt 5.13 where the replacement is only in Qt 5.11, and the only platform that we will no longer support in comparison is macOS 10.10

Br, Eike

-- 
Eike Ziller
Principal Software Engineer

The Qt Company GmbH
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