Add arm64 back

[AaronDewes]

This adds ARM64 again. Many people wanted this in Desktop, and this would help to add it. I also made it a bit faster.

Changes to speed up ARM64

• Use two parallel make jobs
• Compile directly on ARM64 instead of cross-compiling
• Don't use Docker anymore
• Use ccache

[niik]

Many people wanted this in Desktop

Hey @AaronDewes 👋 Could you provide some links to this? I was aware of the initiative to support ARM64 on Windows (desktop/desktop#9034) but the arm64 work we removed in #315 was specifically for Linux which isn't a supported platform for GitHub Desktop at the moment

[AaronDewes]

It's at the Linux fork: shiftkey/desktop#251

[AaronDewes]

It should now build directly on arm64, so it doesn't cross-compile anymore, which should speed up the build.

[AaronDewes]

The macOS builds are failing, but I don't think it's caused by this PR.

[AaronDewes]

I don't know why Ubuntu and macOS builds are failing, macOS just seems to clone from an invalid repo: https://travis-ci.org/github/desktop/dugite-native/jobs/703526404#L860.

[AaronDewes]

ARM64 still takes a bit longer, but not 10 minutes anymore. Ubuntu builds are fixed now.

[AaronDewes]

I've rebased it now. The arm64 build takes about 5 minutes now, macOS is still failing for some reasons.

[AaronDewes]

Seems impossible again now, GitHub actions has no arm64 support and it would be really slow again

[theofficialgman]

github actions has self hosted arm/arm64 support... is that not an option?

[theofficialgman]

https://aws.amazon.com/blogs/compute/building-arm64-applications-on-aws-graviton2-using-the-aws-cdk-and-self-hosted-runners-for-github-actions/
info here on how to do that ^