Add darwin arm64 builds

[dzbarsky]

Github claims they have arm64 runners but doesn't seem like they enabled them for free plans. So for now, we cross-compile from intel and skip tests. I verified that some basic smoketests passed on my M1.

[sylvestre]

@dzbarsky nice to see you here, small world :)

[cakebaker]

Thanks for your PR!

[dzbarsky]

@cakebaker Thanks for merging! I think we need a tagged release to trigger the builds, do you have one planned any time soon?

[cakebaker]

@dzbarsky I don't know when the next release is planned as we don't have a fixed release schedule. Maybe @sylvestre can tell you more as he usually does the releases.

[sylvestre]

sure
@dzbarsky is that urgent? thanks

[tertsdiepraam]

@dzbarsky Isn't it running on main now? For example here: https://github.com/uutils/coreutils/actions/runs/6841104107/job/18601127873

Or do you specifically want artifacts built for this target?

[DavidZbarsky-at]

Yes, I'd like to consume the released artifacts. It's not super urgent, but it is blocking increased usage of this project in bazel-contrib/bazel-lib#622, which is a pretty core part of the Bazel ecosystem at this point, since a lot of people use M1/M2 for local development. I'd love to get that in before they ship their 2.0, which is probably soonish but could wait for this fix.

I considered publishing my own binaries but it's less sketchy to have them come from the canonical upstream :)