Release Cosmopolitan v3.6.0

This release is an atomic upgrade to GCC 14.1.0 with C23 and C++23

third_party/libcxx/__math/copysign.h

@@ -0,0 +1,45 @@
+//===----------------------------------------------------------------------===//
+//
+// 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___MATH_COPYSIGN_H
+#define _LIBCPP___MATH_COPYSIGN_H
+
+#include <__config>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_arithmetic.h>
+#include <__type_traits/promote.h>
+#include <limits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace __math {
+
+// copysign
+
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI float copysign(float __x, float __y) _NOEXCEPT {
+  return ::__builtin_copysignf(__x, __y);
+}
+
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI long double copysign(long double __x, long double __y) _NOEXCEPT {
+  return ::__builtin_copysignl(__x, __y);
+}
+
+template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI typename __promote<_A1, _A2>::type copysign(_A1 __x, _A2 __y) _NOEXCEPT {
+  return ::__builtin_copysign(__x, __y);
+}
+
+} // namespace __math
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MATH_COPYSIGN_H