Qt6 and MSVC 2019 Support

[dpaulat]

This pull request supports MSVC 2019 and Qt 6.1.0. Backward compatibility with Qt5 has been retained.

• No visuals have been impacted
• Tests have been updated for MSVC 2019. A few tests have been disabled, due to Windows platform support. Tests have been verified as passing using MSVC 2019 16.10 (14.29.30037) using the 64-bit compiler, with Qt 6.1.0.
• No API changes have been made
• Only Qt (and Windows) functionality should be impacted by this PR

Launch Checklist

• briefly describe the changes in this PR
• include before/after visuals or gifs if this PR includes visual changes
• write tests for all new functionality
• document any changes to public APIs
• tagged @mapbox/maps-android @mapbox/maps-ios @mapbox/core-sdk if this PR adds or updates a public API
• tagged @mapbox/gl-js if this PR includes shader changes or needs a js port
• apply needs changelog label if a changelog is needed (remove label when added)
• Requires an update to boost headers before merging: Fix proto/generate.hpp for msvc2019 mapbox-gl-native-boost#2

[dpaulat]

Merging of this pull request should resolve the following issues:

• Mapbox GL not supporting in MSVC in Qt windows platform.  #16507
• Zip for compiling mapbox-gl-native with MSVC 2017 (15.6.3)[qt] #11617

[ntadej]

This repository is no longer under (open) development. It might be more useful if you port this MR to https://github.com/maplibre/maplibre-gl-native.

[dpaulat]

This repository is no longer under (open) development. It might be more useful if you port this MR to https://github.com/maplibre/maplibre-gl-native.

Great! I was concerned when I saw other pull requests getting ignored. Glad to see there's a fork with an active community. I'll revisit this in the next couple weeks, and reopen the pull request if maplibre is missing the support I need.

[dpaulat]

This repository is no longer under (open) development. It might be more useful if you port this MR to https://github.com/maplibre/maplibre-gl-native.

I have something in-work. It'll take me at least a few days to get a PR ready. There have been a few breaking changes on the master branch. Your PR helps, but I still need to fix some other errors and add at least a zlib dependency for mbtiles.

[ntadej]

Thanks for looking into it!

We probably don't have to fix all at once. My initial goal is to have something build to setup the CI and then fix the remaining issues.