Add Linux arm64 support

[dromer]

We are starting to see people wanting to use plugdata and the Heavy toolchain on arm64, so we may want to figure out how to add this architecture.

[JoshuaACNewman]

I've got academic computer science contacts over here. Do you know where the gaps are?

[dromer]

We need to replace/reimplement https://github.com/theopolis/build-anywhere

But I'm considering moving things to a docker setup .. not sure yet ..

Also not sure what "academic computer science contacts" can really do here, since it's not really an academic exercise.

[JoshuaACNewman]

Are you suggesting that I shouldn't ask interested parties?

[dromer]

No, but said qualifications should not depend on where they work :P