It's used only as a dev dependency in 5 crates.

Depender (with downloads and own rev deps) build-context version
1.3M 80 portable-atomic dev ^0.1
69K 6 cargo-config2 dev ^0.1
25K cargo-hack dev ^0.1
900 atomic-maybe-uninit dev ^0.1
atomic-memcpy dev ^0.1