Upgrade to 2022-era LLVM LIBCXX

third_party/libcxx/__format/formatter.h

@@ -0,0 +1,54 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMATTER_H
+#define _LIBCPP___FORMAT_FORMATTER_H
+
+#include <__availability>
+#include <__config>
+#include <__format/format_fwd.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 20
+
+/// The default formatter template.
+///
+/// [format.formatter.spec]/5
+/// If F is a disabled specialization of formatter, these values are false:
+/// - is_default_constructible_v<F>,
+/// - is_copy_constructible_v<F>,
+/// - is_move_constructible_v<F>,
+/// - is_copy_assignable<F>, and
+/// - is_move_assignable<F>.
+template <class _Tp, class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter {
+  formatter() = delete;
+  formatter(const formatter&) = delete;
+  formatter& operator=(const formatter&) = delete;
+};
+
+#  if _LIBCPP_STD_VER >= 23
+
+template <class _Tp>
+_LIBCPP_HIDE_FROM_ABI constexpr void __set_debug_format(_Tp& __formatter) {
+  if constexpr (requires { __formatter.set_debug_format(); })
+    __formatter.set_debug_format();
+}
+
+#  endif // _LIBCPP_STD_VER >= 23
+#endif   // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FORMAT_FORMATTER_H