Add riscv64-linux support

[Xeonacid]

Added separate Dockerfiles for riscv64 as suggested by #219 (comment).

RISC-V needs atomic linked which is added to LINUX_ALLOW_SYSTEM_LIBRARIES.

Tested locally with ./build-linux.py --target-triple riscv64-unknown-linux-gnu --python cpython-{3.9,3.10,3.11,3.12,3.13,3.14} and all build fine.

CI is added but not tested yet. I'd like the PR to test itself :P

Closes #388

[Xeonacid]

The CI check is finished but no linux build. Am I doing anything wrong? Or is there anyway I can trigger it? 🤔

[zanieb]

Thanks for the pull request & welcome to the project!

The error is in the GitHub Actions panel 😭

linux: Strategy expansion exceeded 256 results for job 'build'

We've hit the GitHub limit for a matrix. This reveals my main concern about this change — this project already builds and publishes a lot of artifacts and there needs to be clear demand for additions.

[zanieb]

Regarding the GitHub matrix limit.. we're bound to encounter this regardless. We'll need to add some sort of matrix sharding anyway.

[zanieb]

I implemented sharding, but also added the requisite labels to your pull request to run a subset of our CI matrix.

[Xeonacid]

We've hit the GitHub limit for a matrix. This reveals my main concern about this change — this project already builds and publishes a lot of artifacts and there needs to be clear demand for additions.

We are Arch Linux RISC-V packagers. Some packages, like bazel and uv, require a python-build-standalone artifact when building or testing. Adding the riscv64 architecture for this project would be a great help for our packaging!

[zanieb]

We might need to make this conditional

See

• libatomic dependency may be problematic #410
• Scope libatomic allowance to MIPS on Python 3.13 #411

[zanieb]

We'll discuss whether or not we're comfortable maintaining this as a team and get back to you.

[Xeonacid]

We'll discuss whether or not we're comfortable maintaining this as a team and get back to you.

Hoping for good news!

Adding RISC-V support is a forward-looking investment, as its open-source architecture and rapidly growing ecosystem position it to surpass like PPC and s390x, ensuring broader adoption and future-proofing the project.

I'd like to (co-)maintain the riscv architecture if it is an option for you.

[zanieb]

Thanks for the contribution :)