Add Rust for Linux auto CI job

[Kobzol]

This PR adds an auto CI job that checks if Rust for Linux (RfL) still compiles with the latest version of the compiler and the standard library. If not, we should ideally ping the RfL ping group.

[ojeda]

Thanks for this again! Some more comments/thoughts below...

I guess depending on how things go, i.e. how many failures we get and where they fail most, we could consider reducing or increasing the scope.

[Kobzol]

I think that the last thing required here is to select some reasonable initial commit. @ojeda any suggestions? I tried the commit that you have sent me before, but it was not found in the repo I think (maybe git just couldn't work with the shorter SHA though).

Is there any more up-to-date commit that I could use instead of master?

[ojeda]

I tried the commit that you have sent me before, but it was not found in the repo I think (maybe git just couldn't work with the shorter SHA though).

The commit exists, but you probably need something like:

mkdir linux
git -C linux init
git -C linux remote add origin https://github.com/torvalds/linux.git
git -C linux fetch --depth 1 origin 8f5b5f78113e881cb8570c961b0dc42b218a1b9e
git -C linux checkout FETCH_HEAD

instead of --branch. Another way is using the archive URL, e.g. https://github.com/torvalds/linux/archive/8f5b5f78113e.tar.gz.

Also, later today Linus will likely tag v6.10-rc1, which we could also use.

[ojeda]

Is there any more up-to-date commit that I could use instead of master?

Not sure what you mean, master is the latest in Linus' (and generally should not be used, since it will move). Do you mean something in the RFL repository?

[Kobzol]

Not sure what you mean, master is the latest in Linus' (and generally should not be used, since it will move). Do you mean something in the RFL repository?

Sorry, I meant "what is the most up-to-date commit SHA that works with RfL". master is not a stable ref, ofc.

[ojeda]

Both should work (i.e. the one I gave you as well as the current master, i.e. c13320499ba0efd93174ef6462ae8a7a2933f6e7).

[ojeda]

If you want to use the RFL repository as the base URL, I can push those commits there too.

[Kobzol]

No need for now, if it works with upstream Linux. I changed the commit SHA (thanks for the code to checkout a single commit!), let's see if everything still works.

[ojeda]

My pleasure!

[Kobzol]

Ok, looks like it is working, this should be ready for a review now.

r? @Mark-Simulacrum

@rustbot ready

Successful CI run: https://github.com/rust-lang/rust/actions/runs/9243326050/job/25427322274?pr=125209 (~12 minutes on a 8 core CI runner).

[vincenzopalazzo]

I am not an infra expert, but this patch LGMT.