rust-lang/rust — pull request #15066 by pcwalton (2014-06-21 00:07:27+00:00)
Title: librustc: Feature gate lang items and intrinsics.

If you define lang items in your crate, add `#[feature(lang_items)]`.

If you define intrinsics (`extern "rust-intrinsic"`), add
`#[feature(intrinsics)]`.

Closes #12858.

[breaking-change]

r? @brson