error[E0658]: the `linkage` attribute is experimental and not portable across platforms --> $DIR/linkage4.rs:1:1 | LL | #[linkage = "external"] | ^^^^^^^^^^^^^^^^^^^^^^^ | = note: see issue #29603 for more information = help: add `#![feature(linkage)]` to the crate attributes to enable = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0658`.