Natron 2.6 w/ Qt 5 support (track progress)

[devernay]

This issue tracks Qt5 support progress, and replaces #256

Feel free to edit this issue, and use comments for discussion.

Target release

We will release 2.6 with Qt5.

Bugs introduced by Qt5

• (Bug): Qt5: Knob background color doesn't change color when setting keyframe or expression #846

Checklist:

Natron GUI:

• File dialog
• NodeGraph
• Properties panels - affected by (Bug): Qt5: Knob background color doesn't change color when setting keyframe or expression #846

OS Support

Windows

• Build (MinGW)
• Build (MSVC)
• Binary distribution

Linux

• Build (CentOS7+DTS11, docker image)
• Binary distribution (installer)
• Binary distribution (no installer)

macOS

• Build (10.9) (Qt5 requires 10.12)
• Build (10.15)
• Build (12.x Intel)
• Build (12.x M1)
• Binary distribution (Intel)
• Binary distribution (M1)

[rodlie]

So, are we going to distribute just qtbase or qt-everything?

[YakoYakoYokuYoku]

Preferably QtBase only for Windows and MacOS, otherwise for Linux QtWayland could be added too if we want support for Wayland, also I'm planning to make RB-2.6 compatible with Qt6, which also provides QtHttpServer.