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Publish Windows usage guidance
Currently our Windows binary distributions have relatively little documentation despite being a bit tricky to use correctly. In particular, linking against native libraries requires that the user use msys2's `CLANG64` [environment](https://www.msys2.org/docs/environments/). This is a change from the status quo prior to 9.4, when users had to use the `MINGW64` environment. We should advertise this change.
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