Qt6 support #2144
Description
Follow up ticket to #2141 tracking its implementation.
What I'm heading for is to allow compiling Hydrogen using both Qt5 and Qt6. Not long ago (I don't find the issue right now) someone ask whether we could support even more ancient Qt versions (below 5.7). Dropping Qt5 support will most probably be hurtful for people with legacy hardware/systems or less mainstream OSs.
However, I don't want to increase the complexity of the code base significantly with introducing tons of #ifdefs. After all, there have been quite some changes between Qt5 and Qt6. The goal is to still support Qt 5.15. Older versions will probably be incompatible with the changes introduced in here.
- Compiling Hydrogen from source should still use Qt5 per default. After all, we introduce this is a patch release within the 1.2.X release line and do not want to break downstream build pipelines.
- Use Qt6 in our Linux test pipeline (to have at least one Qt6 build)
-
AppImage artifacts should use Qt6 -
macOS artifacts should use Qt6 -
Windows artifacts should use Qt6
Why is it introduced in a patch release within 1.2 and not just in the upcoming 2.0 version? Because 2.0 will still take a lot of time. Plus, some people might not like changes introduced in 2.0 and for those I intend to supply the 1.2.X release line with patches for some time even after the release of 2.0.