ci: add riscv64 release binary via cross-rs

[gounthar]

Adds riscv64gc-unknown-linux-musl to the release matrix using cross-rs for cross-compilation on a standard ubuntu-24.04 runner, as discussed in #9183.

Changes:

• Add linux-riscv64-musl to the build matrix with use_cross: true
• Install cross before the build step (only for riscv64)
• Use cross build instead of cargo build for riscv64; all other targets are unchanged

Closes #9183

[PhilipMetzger]

please move the Closes line into the commit description to adhere to our commit style.

[gounthar]

Done, moved the Closes line into the commit description. Thanks for the heads-up on the style.

[OctopusET]

I believe release version of cross-rs (https://github.com/cross-rs/cross/releases/tag/v0.2.5) doesn't support some targets.
sharkdp/bat#3533

[gounthar]

Good catch, thank you! I've updated to install cross from git at a pinned commit (f86fd03), following the same approach as sharkdp/bat#3533. I should have checked the released version's target support before submitting.

[gounthar]

Thanks for the pointer. Moved the change to binaries.yml and reverted release.yml. Build is running on the fork's main now: https://github.com/gounthar/jj/actions/runs/23817622745

[thoughtpolice]

Thank you! Looks like it worked, but the binary itself is still dynamically linked:

> file jj
jj: ELF 64-bit LSB pie executable, UCB RISC-V, RVC, double-float ABI, version 1 (SYSV), dynamically linked, interpreter /lib/ld-musl-riscv64.so.1, not stripped

Perhaps this is something to do with musl riscv? Or cross-rs? I'm not sure why static linking wouldn't be the default here, but we should preserve this behavior here too (a good example of why I wanted to produce nightly binaries and not releases yet!)

[gounthar]

Thanks for checking. 😊
I think that is the cross-rs toolchain for riscv64gc-unknown-linux-musl not defaulting to static linking, unlike native musl builds where musl-gcc links statically by default. 🤷

I should have verified the binary type before submitting. I just pushed a fix: it adds -C target-feature=+crt-static via RUSTFLAGS for that matrix entry, which should produce a fully static binary matching the x86_64-musl and aarch64-musl outputs.

Sorry for the oversight.

[PhilipMetzger]

You can squash the second commit into the first one, as we generally don't add commits to address reviews. Thanks.

[gounthar]

Done, squashed both commits into one. The static linking fix and the Closes line are now part of the original commit. Thanks for the guidance. 🙏

[thoughtpolice]

Would you mind pushing to your repo once more and getting a static binary out, just so we can do a double check? Thanks.

[PhilipMetzger]

nit: This probably should be in https://github.com/jj-vcs/jj/blob/main/.cargo/config-ci.toml.

[gounthar]

Pushed the squashed commit (with RUSTFLAGS=-C target-feature=+crt-static) to the fork's main. Build running: https://github.com/gounthar/jj/actions/runs/23999598196

[gounthar]

Build passed; linux-riscv64-musl job succeeded: https://github.com/gounthar/jj/actions/runs/23999598196/job/69993388910

Could you download the artifact and verify file jj shows statically linked?