This was motivated by the fact that recording was crashing on the native
M1 build. That ended up being mostly a PEBKAC problem - turns out the
Mac Mini has no built-in microphone 🤦.
I still thinks this has some value though - it doesn't crash in such
cases, and probably doesn't suffer from the problem shown in this thread
either:
https://forums.ankiweb.net/t/anki-crashes-when-trying-to-record-on-mac/14764
For now, this is only enabled when running on arm64. If it turns out to
be reliable, it could be offered as an option on amd64 as well.
More pleasant to work with than ObjectiveC, which will help with the
following commit.
Swift libraries weren't added to macOS until 10.14.4, so theme
autodetection will fail on 10.14.0-10.14.3. The Qt6 build will have its
minimum version bumped to 10.14.4; the Qt5 build will remain on 10.13.4.
Bazel's rules_swift doesn't currently support building Swift dylibs, so
we need to invoke swiftc directly via a genrule().
