Put every Android build artefact in target/android/
This works around #20380 at the cost of rebuilding build-only dependencies twice,
once for normal builds and once for android builds.
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Update the manifest twice to work around manifest generation issue.
My theory is that the new VCS-based cache that's used when generating the manifest gets confused when files that match a gitignore rule are added for the first time. Updating the manifest twice makes the problematic files disappear from the manifest, and I'm not inclined to spend any more time chasing this bug. Fixes#22275.
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Add background hang monitor
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Early feedback welcome, still need to ~~actually integrate it in the constellation message loop, and~~ use it in Layout and Script...
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`homebrew install` could exit with errors like:
```
Error: cmake 3.12.4 is already installed
To upgrade to 3.13.0, run `brew upgrade cmake`
```
This solution is the one recommended in https://github.com/Homebrew/brew/issues/2491
Package and release the Servo magicleap app
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Package the Magic Leap Servo2D app, and build and release it nightly.
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