Remove -Z link-native-libraries=no default

[hoodmane]

We haven't wanted this for a long time

[ryanking13]

I enabled integration test.

Don't we need to update the default rust toolchain version too to make this work?

Also, we tested this in #42 but somehow the downstream PR is closed. Do you remember what kind of error we faced at that time?

[hoodmane]

We're overriding this in Makefile.envs:
https://github.com/pyodide/pyodide/blob/main/Makefile.envs#L15

[ryanking13]

We're overriding this in Makefile.envs:
https://github.com/pyodide/pyodide/blob/main/Makefile.envs#L15

Yes, but the config in pyproject.toml dominates the one in the Makefile.envs. So we can test set custom rustflags overwriting the default one.

[hoodmane]

We clearly don't want this as a default. Presumably we can add it explicitly to any recipe that needs it?

[hoodmane]

Anyways I'd like to switch to stable Rust in the next few months and to do that we need to stop passing unstable flags.

[ryanking13]

We clearly don't want this as a default. Presumably we can add it explicitly to any recipe that needs it?

Sounds reasonable.