[libc] continues header cleanup process (#65556)

cjdb · gchatelet · web-flow · commit b4d6c0f7c71e · 2023-09-07T08:24:31.000+02:00
* replaces `add_rvalue_reference_t` with `is_rvalue_reference_t`
* includes `"stddef.h"` for `size_t` include

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Co-authored-by: Guillaume Chatelet &lt;gchatelet@google.com&gt;
diff --git a/libc/src/__support/CPP/type_traits/is_rvalue_reference.h b/libc/src/__support/CPP/type_traits/is_rvalue_reference.h
@@ -25,7 +25,8 @@ template <typename T> struct is_rvalue_reference : public false_type {};
 template <typename T> struct is_rvalue_reference<T &&> : public true_type {};
 #endif
 template <class T>
-using add_rvalue_reference_t = typename add_rvalue_reference<T>::type;
+LIBC_INLINE_VAR constexpr bool is_rvalue_reference_v =
+    is_rvalue_reference<T>::value;
 
 } // namespace __llvm_libc::cpp
 
diff --git a/libc/src/__support/CPP/type_traits/remove_extent.h b/libc/src/__support/CPP/type_traits/remove_extent.h
@@ -9,6 +9,7 @@
 #define LLVM_LIBC_SRC_SUPPORT_CPP_TYPE_TRAITS_REMOVE_EXTENT_H
 
 #include "src/__support/CPP/type_traits/type_identity.h"
+#include "stddef.h" // size_t
 
 namespace __llvm_libc::cpp {
 
