Fix building for Mac Catalyst

[madsmtm]

Without this change, we end up passing aarch64-apple-ios26.0-macabimacabi to the compiler, which is definitely wrong.

The core change here is to handle this in from_cargo_environment_variables as well, the rest is just a cleanup now that target.env contains the canonical value (and target.abi).

See also the previous #1517 and #1534.

I really should've checked that this worked in cc-rs before landing rust-lang/rust#139451, sorry about that!

[NobodyXu]

Thanks!

Can you run the "Test nightly rustc targets and add issue comment if changed" just to make sure there's no regression?

[madsmtm]

Can you run the "Test nightly rustc targets and add issue comment if changed" just to make sure there's no regression?

I ran the following locally, and that worked:

RUSTFLAGS=--cfg=rustc_target_test cargo +nightly test --lib

I don't know how to trigger a workflow on a PR?

[NobodyXu]

Thank you!

As oong as it can pass all tests, I'm be ok with it