Build for aarch64-apple-darwin

[shepmaster]

No description provided.

[kinnison]

The macos changes need to go in the actions template, otherwise they'll be lost next time we regenerate the actions files. Also I think the set-env stuff needs changing now :D

[shepmaster]

Ah, I was waiting for #2515 and it looks like it’s been addressed.

[shepmaster]

The macos changes need to go in the actions template

Done.

the set-env stuff needs changing now

Done.

[kinnison]

As a final point before I merge this, have you confirmed that rustup believes this is a valid host triple?

[kinnison]

I think it should do, and I seem to recall you running your cross-built binary on an aarch64 mac, but I just want to be sure

[shepmaster]

have you confirmed that rustup believes this is a valid host triple?

If I understand you, I think so. rustup actually works “as-is” today:

arch --x86_64 \
sh <(curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs) \
--default-host aarch64-apple-darwin \
--default-toolchain nightly

I expect that this PR removes the need to bring in the x86-64 emulator. A future change to the shell script should reduce it to the usual one-liner.