Remove extern crate rustc_data_structures from numerous crates.

compiler/rustc_hir/src/hir.rs

@@ -3863,6 +3863,7 @@ impl<'hir> Node<'hir> {
 #[cfg(target_pointer_width = "64")]
 mod size_asserts {
     use super::*;
+    use rustc_data_structures::static_assert_size;
     // tidy-alphabetical-start
     static_assert_size!(Block<'_>, 48);
     static_assert_size!(Body<'_>, 24);

compiler/rustc_hir/src/lang_items.rs

@@ -56,7 +56,7 @@ macro_rules! language_item_table {
         $( $(#[$attr:meta])* $variant:ident, $module:ident :: $name:ident, $method:ident, $target:expr, $generics:expr; )*
     ) => {
 
-        enum_from_u32! {
+        rustc_data_structures::enum_from_u32! {
             /// A representation of all the valid lang items in Rust.
             #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable)]
             pub enum LangItem {

compiler/rustc_hir/src/lib.rs

@@ -13,9 +13,6 @@
 #[macro_use]
 extern crate tracing;
 
-#[macro_use]
-extern crate rustc_data_structures;
-
 extern crate self as rustc_hir;
 
 mod arena;