Remove cross-compilation from linux x86 in Rust CI

[marcoieni]

GitHub introduced free arm runners, which are faster than x86 free runners.

There are many jobs where we use the x86 free runner to cross compile because a free arm runner wasn't available at the time.

Tasks

Remove cross-compilation from x86 to arm

• list all linux jobs that cross compile from x86 to aarch64
• convert those jobs to remove cross-compilation of the architecture. Example PR: CI: move dist-arm-linux to a free ARM runner rust#135774

Remove cross-compilation from x86 to all other architectures

• list all linux jobs that cross compile from x86 to the other architectures (e.g. powerpc)
• convert those jobs if the new runner is faster and cheaper

Additional context

Discussed in zulip.

[nikic]

I find the description in this issue quite confusing. If I'm understanding correctly, what you're actually proposing is to use arm runners instead of x86 runners as the host for builds that use cross-compilation, not to remove the cross-compilation. For dist-arm-linux, you'd still cross-compile from ARM to ARM, right? You're not proposing to remove the use of crosstool-ng?

[marcoieni]

If I'm understanding correctly, what you're actually proposing is to use arm runners instead of x86 runners as the host for builds that use cross-compilation, not to remove the cross-compilation.

Yes

For dist-arm-linux, you'd still cross-compile from ARM to ARM, right?

This issue doesn't regard dist-arm-linux as the host is not x86. 👍

You're not proposing to remove the use of crosstool-ng?

No

So I think you got it right, sorry for the poor explanation!