Auto merge of #124482 - spastorino:unsafe-extern-blocks, r=oli-obk

Unsafe extern blocks

This implements RFC 3484.

Tracking issue #123743 and RFC https://github.com/rust-lang/rfcs/pull/3484

This is better reviewed commit by commit.

clippy_utils/src/ast_utils.rs

@@ -308,13 +308,15 @@ pub fn eq_item_kind(l: &ItemKind, r: &ItemKind) -> bool {
                 ty: lt,
                 mutability: lm,
                 expr: le,
+                safety: ls,
             }),
             Static(box StaticItem {
                 ty: rt,
                 mutability: rm,
                 expr: re,
+                safety: rs,
             }),
-        ) => lm == rm && eq_ty(lt, rt) && eq_expr_opt(le, re),
+        ) => lm == rm && ls == rs && eq_ty(lt, rt) && eq_expr_opt(le, re),
         (
             Const(box ConstItem {
                 defaultness: ld,
@@ -451,13 +453,15 @@ pub fn eq_foreign_item_kind(l: &ForeignItemKind, r: &ForeignItemKind) -> bool {
                 ty: lt,
                 mutability: lm,
                 expr: le,
+                safety: ls,
             }),
             Static(box StaticForeignItem {
                 ty: rt,
                 mutability: rm,
                 expr: re,
+                safety: rs,
             }),
-        ) => lm == rm && eq_ty(lt, rt) && eq_expr_opt(le, re),
+        ) => lm == rm && eq_ty(lt, rt) && eq_expr_opt(le, re) && ls == rs,
         (
             Fn(box ast::Fn {
                 defaultness: ld,