Change only_local to enum type and change the macros to always require a variant of that enum.

compiler/rustc_feature/src/lib.rs

@@ -124,7 +124,7 @@ pub fn find_feature_issue(feature: Symbol, issue: GateIssue) -> Option<NonZero<u
 pub use accepted::ACCEPTED_FEATURES;
 pub use builtin_attrs::AttributeDuplicates;
 pub use builtin_attrs::{
-    deprecated_attributes, find_gated_cfg, is_builtin_attr_name, is_builtin_only_local,
+    deprecated_attributes, encode_cross_crate, find_gated_cfg, is_builtin_attr_name,
     is_valid_for_get_attr, AttributeGate, AttributeTemplate, AttributeType, BuiltinAttribute,
     GatedCfg, BUILTIN_ATTRIBUTES, BUILTIN_ATTRIBUTE_MAP,
 };