`cargo check --all-targets --all-features` should succeed

[xtqqczze]

cargo +nightly check -q --workspace --all-targets --all-features

• Make rustc-dep-of-std work with extra-traits #5492
• libc: Make rustc-dep-of-std work in tests #5495
• cleanup: remove unused dependencies #5494

[tgross35]

Those PRs have merged so this works now