Derive Clone for TypeId.

src/libcore/intrinsics.rs

@@ -536,7 +536,7 @@ extern "rust-intrinsic" {
 /// `TypeId` represents a globally unique identifier for a type
 #[lang="type_id"] // This needs to be kept in lockstep with the code in trans/intrinsic.rs and
                   // middle/lang_items.rs
-#[deriving(PartialEq, Eq, Show)]
+#[deriving(Clone, PartialEq, Eq, Show)]
 pub struct TypeId {
     t: u64,
 }