Cryptography v36.0.2 w/ Rust

[hoodmane]

Resolves #1973.

[hoodmane]

@henryiii the code spell is trying to correct crate ==> create again

[hoodmane]

This is currently missing a fix for chronotope/chrono#519, but once we patch chrono it will work.

[henryiii]

Again? We can add crate to the wordlist.

[henryiii]

https://github.com/hoodmane/pyodide/blob/4e476ff33bd20ee00fbf011a9c73ae3bfcf0538e/.pre-commit-config.yaml#L102

Needs to be added here.

[hoodmane]

Okay I think this PR is in good shape now:

1. I removed the need for -Zbuild-std so now we can build with rust stable
2. Ideally RUSTFLAGS would use SIDE_MODULE_LDFLAGS but I can't get it to work
3. The --whole-archive problem is recognized upstream, seems like it's just a matter of time before we work out an appropriate fix. --whole-archive causes trouble when linking rust emscripten-core/emscripten#17109
4. The emscripten_get_now__sig patch is merged upstream https://github.com/emscripten-core/emscripten/pull/17123/files
5. The chrono bug is fixed upstream, but we need them to make a release and cryptography to update the version before we can use it.
6. The instant library looks unmaintained but I opened a PR emscripten_get_now should have no leading underscore sebcrozet/instant#47
7. It would be fantastic to make rust emit .so files rather than emitting .wasm files and having to move them in pywasmcross, but the wasm32-unknown-emscripten target has "dll-suffix": ".wasm" and as far as I can tell this is not configurable without creating a custom target which would require us to maintain complete target metadata and would probably force us back to nightly rust.

[hoodmane]

So there is still a lot that could be improved but given the state of the wasm32-emscripten rust target, I would say we are doing pretty good here.

[ryanking13]

Thanks for your hard work @hoodmane! It looks really cool.
Please update docs about the rust dependency that one should install rust to build cryptography (or when building with PYODIDE_PACKAGES="*" make)

(Probably in https://github.com/pyodide/pyodide/blob/main/docs/development/building-from-sources.md)

[hoodmane]

Probably we should add Rust to the docker image?

[ryanking13]

Probably we should add Rust to the docker image?

Yes I am +1 for it.

[rth]

It would be good to update the documentation, otherwise LGTM as well.

[hoodmane]

I can't get the docker image to work correctly so I reverted that stuff. I think we can deal with that as a followup.

[ryanking13]

Sure, feel free to merge it when you think it is ready. Thanks for your hard work!