lib: establish Zircon libc++ and KTL foundation

1 files changed, 612 insertions, 0 deletions

diff --git a/third_party/libcxx/include/c++/v1/__config b/third_party/libcxx/include/c++/v1/__config
new file mode 100644
index 0000000..942b0a9
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__config
@@ -0,0 +1,612 @@
+// -*- 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___CONFIG
+#define _LIBCPP___CONFIG
+
+#include <__config_site>
+
+#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
+#  pragma GCC system_header
+#endif
+
+#ifdef __cplusplus
+
+#  include <__configuration/abi.h>
+#  include <__configuration/attributes.h>
+#  include <__configuration/availability.h>
+#  include <__configuration/compiler.h>
+#  include <__configuration/experimental.h>
+#  include <__configuration/hardening.h>
+#  include <__configuration/language.h>
+#  include <__configuration/platform.h>
+
+// The attributes supported by clang are documented at https://clang.llvm.org/docs/AttributeReference.html
+
+// _LIBCPP_VERSION represents the version of libc++, which matches the version of LLVM.
+// Given a LLVM release LLVM XX.YY.ZZ (e.g. LLVM 17.0.1 == 17.00.01), _LIBCPP_VERSION is
+// defined to XXYYZZ.
+#  define _LIBCPP_VERSION 230000
+
+#  define _LIBCPP_CONCAT_IMPL(_X, _Y) _X##_Y
+#  define _LIBCPP_CONCAT(_X, _Y) _LIBCPP_CONCAT_IMPL(_X, _Y)
+#  define _LIBCPP_CONCAT3(X, Y, Z) _LIBCPP_CONCAT(X, _LIBCPP_CONCAT(Y, Z))
+
+#  define _LIBCPP_TOSTRING2(x) #x
+#  define _LIBCPP_TOSTRING(x) _LIBCPP_TOSTRING2(x)
+
+#  ifndef __has_constexpr_builtin
+#    define __has_constexpr_builtin(x) 0
+#  endif
+
+// This checks wheter a Clang module is built
+#  ifndef __building_module
+#    define __building_module(...) 0
+#  endif
+
+// '__is_identifier' returns '0' if '__x' is a reserved identifier provided by
+// the compiler and '1' otherwise.
+#  ifndef __is_identifier
+#    define __is_identifier(__x) 1
+#  endif
+
+#  define __has_keyword(__x) !(__is_identifier(__x))
+
+#  ifndef __has_warning
+#    define __has_warning(...) 0
+#  endif
+
+#  if !defined(_LIBCPP_COMPILER_CLANG_BASED) && __cplusplus < 201103L
+#    error "libc++ only supports C++03 with Clang-based compilers. Please enable C++11"
+#  endif
+
+#  if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_NO_VCRUNTIME)
+#    define _LIBCPP_ABI_VCRUNTIME
+#  endif
+
+#  if defined(__MVS__)
+#    include <features.h> // for __NATIVE_ASCII_F
+#  endif
+
+#  if defined(_WIN32)
+#    define _LIBCPP_WIN32API
+#    define _LIBCPP_SHORT_WCHAR 1
+// Both MinGW and native MSVC provide a "MSVC"-like environment
+#    define _LIBCPP_MSVCRT_LIKE
+// If mingw not explicitly detected, assume using MS C runtime only if
+// a MS compatibility version is specified.
+#    if defined(_MSC_VER) && !defined(__MINGW32__)
+#      define _LIBCPP_MSVCRT // Using Microsoft's C Runtime library
+#    endif
+#    if (defined(_M_AMD64) || defined(__x86_64__)) || (defined(_M_ARM) || defined(__arm__))
+#      define _LIBCPP_HAS_BITSCAN64 1
+#    else
+#      define _LIBCPP_HAS_BITSCAN64 0
+#    endif
+#    define _LIBCPP_HAS_OPEN_WITH_WCHAR 1
+#  else
+#    define _LIBCPP_HAS_OPEN_WITH_WCHAR 0
+#    define _LIBCPP_HAS_BITSCAN64 0
+#  endif // defined(_WIN32)
+
+#  if defined(_AIX) && !defined(__64BIT__)
+// The size of wchar is 2 byte on 32-bit mode on AIX.
+#    define _LIBCPP_SHORT_WCHAR 1
+#  endif
+
+// Libc++ supports various implementations of std::random_device.
+//
+// _LIBCPP_USING_DEV_RANDOM
+//      Read entropy from the given file, by default `/dev/urandom`.
+//      If a token is provided, it is assumed to be the path to a file
+//      to read entropy from. This is the default behavior if nothing
+//      else is specified. This implementation requires storing state
+//      inside `std::random_device`.
+//
+// _LIBCPP_USING_ARC4_RANDOM
+//      Use arc4random(). This allows obtaining random data even when
+//      using sandboxing mechanisms. On some platforms like Apple, this
+//      is the recommended source of entropy for user-space programs.
+//      When this option is used, the token passed to `std::random_device`'s
+//      constructor *must* be "/dev/urandom" -- anything else is an error.
+//
+// _LIBCPP_USING_GETENTROPY
+//      Use getentropy().
+//      When this option is used, the token passed to `std::random_device`'s
+//      constructor *must* be "/dev/urandom" -- anything else is an error.
+//
+// _LIBCPP_USING_FUCHSIA_CPRNG
+//      Use Fuchsia's zx_cprng_draw() system call, which is specified to
+//      deliver high-quality entropy and cannot fail.
+//      When this option is used, the token passed to `std::random_device`'s
+//      constructor *must* be "/dev/urandom" -- anything else is an error.
+//
+// _LIBCPP_USING_WIN32_RANDOM
+//      Use rand_s(), for use on Windows.
+//      When this option is used, the token passed to `std::random_device`'s
+//      constructor *must* be "/dev/urandom" -- anything else is an error.
+#  if defined(__APPLE__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) ||                     \
+      defined(__DragonFly__)
+#    define _LIBCPP_USING_ARC4_RANDOM
+#  elif defined(__wasi__) || defined(__EMSCRIPTEN__)
+#    define _LIBCPP_USING_GETENTROPY
+#  elif defined(__Fuchsia__)
+#    define _LIBCPP_USING_FUCHSIA_CPRNG
+#  elif defined(_LIBCPP_WIN32API)
+#    define _LIBCPP_USING_WIN32_RANDOM
+#  else
+#    define _LIBCPP_USING_DEV_RANDOM
+#  endif
+
+#  ifndef _LIBCPP_CXX03_LANG
+
+#    define _LIBCPP_ALIGNOF(...) alignof(__VA_ARGS__)
+#    define _ALIGNAS_TYPE(x) alignas(x)
+#    define _ALIGNAS(x) alignas(x)
+#    define _NOEXCEPT noexcept
+#    define _NOEXCEPT_(...) noexcept(__VA_ARGS__)
+#    define _LIBCPP_CONSTEXPR constexpr
+
+#  else
+
+#    define _LIBCPP_ALIGNOF(...) _Alignof(__VA_ARGS__)
+#    define _ALIGNAS_TYPE(x) __attribute__((__aligned__(_LIBCPP_ALIGNOF(x))))
+#    define _ALIGNAS(x) __attribute__((__aligned__(x)))
+#    define nullptr __nullptr
+#    define _NOEXCEPT throw()
+#    define _NOEXCEPT_(...)
+#    define static_assert(...) _Static_assert(__VA_ARGS__)
+#    define decltype(...) __decltype(__VA_ARGS__)
+#    define _LIBCPP_CONSTEXPR
+
+typedef __char16_t char16_t;
+typedef __char32_t char32_t;
+
+#  endif
+
+#  define _LIBCPP_PREFERRED_ALIGNOF(_Tp) __alignof(_Tp)
+
+#  if __has_extension(blocks) && defined(__APPLE__)
+#    define _LIBCPP_HAS_BLOCKS_RUNTIME 1
+#  else
+#    define _LIBCPP_HAS_BLOCKS_RUNTIME 0
+#  endif
+
+#  ifdef _LIBCPP_COMPILER_CLANG_BASED
+#    define _LIBCPP_DIAGNOSTIC_PUSH _Pragma("clang diagnostic push")
+#    define _LIBCPP_DIAGNOSTIC_POP _Pragma("clang diagnostic pop")
+#    define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str) _Pragma(_LIBCPP_TOSTRING(clang diagnostic ignored str))
+#    define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str)
+#  elif defined(_LIBCPP_COMPILER_GCC)
+#    define _LIBCPP_DIAGNOSTIC_PUSH _Pragma("GCC diagnostic push")
+#    define _LIBCPP_DIAGNOSTIC_POP _Pragma("GCC diagnostic pop")
+#    define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str)
+#    define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str) _Pragma(_LIBCPP_TOSTRING(GCC diagnostic ignored str))
+#  else
+#    define _LIBCPP_DIAGNOSTIC_PUSH
+#    define _LIBCPP_DIAGNOSTIC_POP
+#    define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str)
+#    define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str)
+#  endif
+
+// Macros to enter and leave a state where deprecation warnings are suppressed.
+#  define _LIBCPP_SUPPRESS_DEPRECATED_PUSH                                                                             \
+    _LIBCPP_DIAGNOSTIC_PUSH _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wdeprecated")                                           \
+        _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wdeprecated-declarations")
+#  define _LIBCPP_SUPPRESS_DEPRECATED_POP _LIBCPP_DIAGNOSTIC_POP
+
+// Clang modules take a significant compile time hit when pushing and popping diagnostics.
+// Since all the headers are marked as system headers unless _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER is defined, we can
+// simply disable this pushing and popping when _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER isn't defined.
+#  ifdef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
+#    define _LIBCPP_PUSH_EXTENSION_DIAGNOSTICS                                                                         \
+      _LIBCPP_DIAGNOSTIC_PUSH                                                                                          \
+      _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++11-extensions")                                                           \
+      _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++14-extensions")                                                           \
+      _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++17-extensions")                                                           \
+      _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++20-extensions")                                                           \
+      _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++23-extensions")                                                           \
+      _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++14-extensions")                                                             \
+      _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++17-extensions")                                                             \
+      _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++20-extensions")                                                             \
+      _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++23-extensions")
+#    define _LIBCPP_POP_EXTENSION_DIAGNOSTICS _LIBCPP_DIAGNOSTIC_POP
+#  else
+#    define _LIBCPP_PUSH_EXTENSION_DIAGNOSTICS
+#    define _LIBCPP_POP_EXTENSION_DIAGNOSTICS
+#  endif
+
+// clang-format off
+
+// The unversioned namespace is used when we want to be ABI compatible with other standard libraries in some way. There
+// are two main categories where that's the case:
+// - Historically, we have made exception types ABI compatible with libstdc++ to allow throwing them between libstdc++
+//   and libc++. This is not used anymore for new exception types, since there is no use-case for it anymore.
+// - Types and functions which are used by the compiler are in the unversioned namespace, since the compiler has to know
+//   their mangling without the appropriate declaration in some cases.
+// If it's not clear whether using the unversioned namespace is the correct thing to do, it's not. The versioned
+// namespace (_LIBCPP_BEGIN_NAMESPACE_STD) should almost always be used.
+#  define _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD                                                                      \
+    _LIBCPP_PUSH_EXTENSION_DIAGNOSTICS namespace _LIBCPP_NAMESPACE_VISIBILITY std {
+
+#  define _LIBCPP_END_UNVERSIONED_NAMESPACE_STD } _LIBCPP_POP_EXTENSION_DIAGNOSTICS
+
+#  define _LIBCPP_BEGIN_NAMESPACE_STD _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD inline namespace _LIBCPP_ABI_NAMESPACE {
+#  define _LIBCPP_END_NAMESPACE_STD } _LIBCPP_END_UNVERSIONED_NAMESPACE_STD
+
+// TODO: This should really be in the versioned namespace
+#define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD namespace experimental {
+#define _LIBCPP_END_NAMESPACE_EXPERIMENTAL } _LIBCPP_END_UNVERSIONED_NAMESPACE_STD
+
+#define _LIBCPP_BEGIN_NAMESPACE_LFTS _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v1 {
+#define _LIBCPP_END_NAMESPACE_LFTS } _LIBCPP_END_NAMESPACE_EXPERIMENTAL
+
+#define _LIBCPP_BEGIN_NAMESPACE_LFTS_V2 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v2 {
+#define _LIBCPP_END_NAMESPACE_LFTS_V2 } _LIBCPP_END_NAMESPACE_EXPERIMENTAL
+
+#ifdef _LIBCPP_ABI_NO_FILESYSTEM_INLINE_NAMESPACE
+#  define _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM _LIBCPP_BEGIN_NAMESPACE_STD namespace filesystem {
+#  define _LIBCPP_END_NAMESPACE_FILESYSTEM } _LIBCPP_END_NAMESPACE_STD
+#else
+#  define _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM _LIBCPP_BEGIN_NAMESPACE_STD                                               \
+                                             inline namespace __fs { namespace filesystem {
+
+#  define _LIBCPP_END_NAMESPACE_FILESYSTEM }} _LIBCPP_END_NAMESPACE_STD
+#endif
+
+// clang-format on
+
+#  if !defined(__SIZEOF_INT128__) || defined(_MSC_VER)
+#    define _LIBCPP_HAS_INT128 0
+#  else
+#    define _LIBCPP_HAS_INT128 1
+#  endif
+
+#  ifdef _LIBCPP_CXX03_LANG
+#    define _LIBCPP_DECLARE_STRONG_ENUM(x)                                                                             \
+      struct _LIBCPP_EXPORTED_FROM_ABI x {                                                                             \
+        enum __lx
+// clang-format off
+#    define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x)                                                                      \
+      __lx __v_;                                                                                                       \
+      _LIBCPP_HIDE_FROM_ABI x(__lx __v) : __v_(__v) {}                                                                 \
+      _LIBCPP_HIDE_FROM_ABI explicit x(int __v) : __v_(static_cast<__lx>(__v)) {}                                      \
+      _LIBCPP_HIDE_FROM_ABI operator int() const { return __v_; }                                                      \
+      };
+// clang-format on
+
+#  else // _LIBCPP_CXX03_LANG
+#    define _LIBCPP_DECLARE_STRONG_ENUM(x) enum class x
+#    define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x)
+#  endif // _LIBCPP_CXX03_LANG
+
+#  ifdef __FreeBSD__
+#    define _DECLARE_C99_LDBL_MATH 1
+#  endif
+
+// If we are getting operator new from the MSVC CRT, then allocation overloads
+// for align_val_t were added in 19.12, aka VS 2017 version 15.3.
+#  if defined(_LIBCPP_MSVCRT) && defined(_MSC_VER) && _MSC_VER < 1912
+#    define _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION 0
+#  elif defined(_LIBCPP_ABI_VCRUNTIME) && !defined(__cpp_aligned_new)
+// We're deferring to Microsoft's STL to provide aligned new et al. We don't
+// have it unless the language feature test macro is defined.
+#    define _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION 0
+#  elif defined(__MVS__)
+#    define _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION 0
+#  else
+#    define _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION 1
+#  endif
+
+#  if !_LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION || (!defined(__cpp_aligned_new) || __cpp_aligned_new < 201606)
+#    define _LIBCPP_HAS_ALIGNED_ALLOCATION 0
+#  else
+#    define _LIBCPP_HAS_ALIGNED_ALLOCATION 1
+#  endif
+
+#  if defined(__APPLE__) || defined(__FreeBSD__)
+#    define _LIBCPP_WCTYPE_IS_MASK
+#  endif
+
+// FIXME: using `#warning` causes diagnostics from system headers which include deprecated headers. This can only be
+// enabled again once https://github.com/llvm/llvm-project/pull/168041 (or a similar feature) has landed, since that
+// allows suppression in system headers.
+#  if defined(__DEPRECATED) && __DEPRECATED && !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS) && 0
+#    define _LIBCPP_DIAGNOSE_DEPRECATED_HEADERS 1
+#  else
+#    define _LIBCPP_DIAGNOSE_DEPRECATED_HEADERS 0
+#  endif
+
+#  if _LIBCPP_STD_VER <= 11
+#    define _LIBCPP_EXPLICIT_SINCE_CXX14
+#  else
+#    define _LIBCPP_EXPLICIT_SINCE_CXX14 explicit
+#  endif
+
+#  if _LIBCPP_STD_VER >= 23
+#    define _LIBCPP_EXPLICIT_SINCE_CXX23 explicit
+#  else
+#    define _LIBCPP_EXPLICIT_SINCE_CXX23
+#  endif
+
+#  if _LIBCPP_STD_VER >= 14
+#    define _LIBCPP_CONSTEXPR_SINCE_CXX14 constexpr
+#  else
+#    define _LIBCPP_CONSTEXPR_SINCE_CXX14
+#  endif
+
+#  if _LIBCPP_STD_VER >= 17
+#    define _LIBCPP_CONSTEXPR_SINCE_CXX17 constexpr
+#  else
+#    define _LIBCPP_CONSTEXPR_SINCE_CXX17
+#  endif
+
+#  if _LIBCPP_STD_VER >= 20
+#    define _LIBCPP_CONSTEXPR_SINCE_CXX20 constexpr
+#  else
+#    define _LIBCPP_CONSTEXPR_SINCE_CXX20
+#  endif
+
+#  if _LIBCPP_STD_VER >= 23
+#    define _LIBCPP_CONSTEXPR_SINCE_CXX23 constexpr
+#  else
+#    define _LIBCPP_CONSTEXPR_SINCE_CXX23
+#  endif
+
+#  if _LIBCPP_STD_VER >= 26
+#    define _LIBCPP_CONSTEXPR_SINCE_CXX26 constexpr
+#  else
+#    define _LIBCPP_CONSTEXPR_SINCE_CXX26
+#  endif
+
+// Thread API
+// clang-format off
+#  if _LIBCPP_HAS_THREADS &&                                                                                           \
+      !_LIBCPP_HAS_THREAD_API_PTHREAD &&                                                                               \
+      !_LIBCPP_HAS_THREAD_API_WIN32 &&                                                                                 \
+      !_LIBCPP_HAS_THREAD_API_EXTERNAL &&                                                                              \
+      !_LIBCPP_HAS_THREAD_API_C11
+
+#    if defined(__FreeBSD__) ||                                                                                        \
+        defined(__wasi__) ||                                                                                           \
+        defined(__NetBSD__) ||                                                                                         \
+        defined(__OpenBSD__) ||                                                                                        \
+        defined(__NuttX__) ||                                                                                          \
+        defined(__linux__) ||                                                                                          \
+        defined(__GNU__) ||                                                                                            \
+        defined(__APPLE__) ||                                                                                          \
+        defined(__MVS__) ||                                                                                            \
+        defined(_AIX) ||                                                                                               \
+        defined(__EMSCRIPTEN__)
+// clang-format on
+#      undef _LIBCPP_HAS_THREAD_API_PTHREAD
+#      define _LIBCPP_HAS_THREAD_API_PTHREAD 1
+#    elif defined(__Fuchsia__)
+// TODO(44575): Switch to C11 thread API when possible.
+#      undef _LIBCPP_HAS_THREAD_API_PTHREAD
+#      define _LIBCPP_HAS_THREAD_API_PTHREAD 1
+#    elif defined(_LIBCPP_WIN32API)
+#      undef _LIBCPP_HAS_THREAD_API_WIN32
+#      define _LIBCPP_HAS_THREAD_API_WIN32 1
+#    else
+#      error "No thread API"
+#    endif // _LIBCPP_HAS_THREAD_API
+#  endif   // _LIBCPP_HAS_THREADS
+
+#  if !_LIBCPP_HAS_THREAD_API_PTHREAD
+#    define _LIBCPP_HAS_COND_CLOCKWAIT 0
+#  elif (defined(__ANDROID__) && __ANDROID_API__ >= 30) || _LIBCPP_GLIBC_PREREQ(2, 30)
+#    define _LIBCPP_HAS_COND_CLOCKWAIT 1
+#  else
+#    define _LIBCPP_HAS_COND_CLOCKWAIT 0
+#  endif
+
+#  if !_LIBCPP_HAS_THREADS && _LIBCPP_HAS_THREAD_API_PTHREAD
+#    error _LIBCPP_HAS_THREAD_API_PTHREAD may only be true when _LIBCPP_HAS_THREADS is true.
+#  endif
+
+#  if !_LIBCPP_HAS_THREADS && _LIBCPP_HAS_THREAD_API_EXTERNAL
+#    error _LIBCPP_HAS_THREAD_API_EXTERNAL may only be true when _LIBCPP_HAS_THREADS is true.
+#  endif
+
+#  if !_LIBCPP_HAS_THREADS && _LIBCPP_HAS_THREAD_API_C11
+#    error _LIBCPP_HAS_THREAD_API_C11 may only be true when _LIBCPP_HAS_THREADS is true.
+#  endif
+
+#  if !_LIBCPP_HAS_MONOTONIC_CLOCK && _LIBCPP_HAS_THREADS
+#    error _LIBCPP_HAS_MONOTONIC_CLOCK may only be false when _LIBCPP_HAS_THREADS is false.
+#  endif
+
+#  if _LIBCPP_HAS_THREADS && !defined(__STDCPP_THREADS__)
+#    define __STDCPP_THREADS__ 1
+#  endif
+
+// The glibc and Bionic implementation of pthreads implements
+// pthread_mutex_destroy as nop for regular mutexes. Additionally, Win32
+// mutexes have no destroy mechanism.
+//
+// This optimization can't be performed on Apple platforms, where
+// pthread_mutex_destroy can allow the kernel to release resources.
+// See https://llvm.org/D64298 for details.
+//
+// TODO(EricWF): Enable this optimization on Bionic after speaking to their
+//               respective stakeholders.
+// clang-format off
+#  if (_LIBCPP_HAS_THREAD_API_PTHREAD && defined(__GLIBC__)) ||                                                        \
+      (_LIBCPP_HAS_THREAD_API_C11 && defined(__Fuchsia__)) ||                                                          \
+       _LIBCPP_HAS_THREAD_API_WIN32
+// clang-format on
+#    define _LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION 1
+#  else
+#    define _LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION 0
+#  endif
+
+// Destroying a condvar is a nop on Windows.
+//
+// This optimization can't be performed on Apple platforms, where
+// pthread_cond_destroy can allow the kernel to release resources.
+// See https://llvm.org/D64298 for details.
+//
+// TODO(EricWF): This is potentially true for some pthread implementations
+// as well.
+#  if (_LIBCPP_HAS_THREAD_API_C11 && defined(__Fuchsia__)) || _LIBCPP_HAS_THREAD_API_WIN32
+#    define _LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION 1
+#  else
+#    define _LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION 0
+#  endif
+
+#  if defined(__BIONIC__) || defined(__NuttX__) || defined(__Fuchsia__) || defined(__wasi__) ||                        \
+      _LIBCPP_HAS_MUSL_LIBC || defined(__OpenBSD__) || _LIBCPP_LIBC_LLVM_LIBC
+#    define _LIBCPP_PROVIDES_DEFAULT_RUNE_TABLE
+#  endif
+
+#  if __has_feature(cxx_atomic) || __has_extension(c_atomic) || __has_keyword(_Atomic)
+#    define _LIBCPP_HAS_C_ATOMIC_IMP 1
+#    define _LIBCPP_HAS_GCC_ATOMIC_IMP 0
+#    define _LIBCPP_HAS_EXTERNAL_ATOMIC_IMP 0
+#  elif defined(_LIBCPP_COMPILER_GCC)
+#    define _LIBCPP_HAS_C_ATOMIC_IMP 0
+#    define _LIBCPP_HAS_GCC_ATOMIC_IMP 1
+#    define _LIBCPP_HAS_EXTERNAL_ATOMIC_IMP 0
+#  endif
+
+#  if !_LIBCPP_HAS_C_ATOMIC_IMP && !_LIBCPP_HAS_GCC_ATOMIC_IMP && !_LIBCPP_HAS_EXTERNAL_ATOMIC_IMP
+#    define _LIBCPP_HAS_ATOMIC_HEADER 0
+#  else
+#    define _LIBCPP_HAS_ATOMIC_HEADER 1
+#    ifndef _LIBCPP_ATOMIC_FLAG_TYPE
+#      define _LIBCPP_ATOMIC_FLAG_TYPE bool
+#    endif
+#  endif
+
+// We often repeat things just for handling wide characters in the library.
+// When wide characters are disabled, it can be useful to have a quick way of
+// disabling it without having to resort to #if-#endif, which has a larger
+// impact on readability.
+#  if !_LIBCPP_HAS_WIDE_CHARACTERS
+#    define _LIBCPP_IF_WIDE_CHARACTERS(...)
+#  else
+#    define _LIBCPP_IF_WIDE_CHARACTERS(...) __VA_ARGS__
+#  endif
+
+// clang-format off
+#  define _LIBCPP_PUSH_MACROS _Pragma("push_macro(\"min\")") _Pragma("push_macro(\"max\")") _Pragma("push_macro(\"refresh\")") _Pragma("push_macro(\"move\")") _Pragma("push_macro(\"erase\")")
+#  define _LIBCPP_POP_MACROS _Pragma("pop_macro(\"min\")") _Pragma("pop_macro(\"max\")") _Pragma("pop_macro(\"refresh\")") _Pragma("pop_macro(\"move\")") _Pragma("pop_macro(\"erase\")")
+// clang-format on
+
+#  ifndef _LIBCPP_NO_AUTO_LINK
+#    if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_BUILDING_LIBRARY)
+#      if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#        pragma comment(lib, "c++.lib")
+#      else
+#        pragma comment(lib, "libc++.lib")
+#      endif
+#    endif // defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_BUILDING_LIBRARY)
+#  endif   // _LIBCPP_NO_AUTO_LINK
+
+// Configures the fopen close-on-exec mode character, if any. This string will
+// be appended to any mode string used by fstream for fopen/fdopen.
+//
+// Not all platforms support this, but it helps avoid fd-leaks on platforms that
+// do.
+#  if defined(__BIONIC__)
+#    define _LIBCPP_FOPEN_CLOEXEC_MODE "e"
+#  else
+#    define _LIBCPP_FOPEN_CLOEXEC_MODE
+#  endif
+
+// c8rtomb() and mbrtoc8() were added in C++20 and C23. Support for these
+// functions is gradually being added to existing C libraries. The conditions
+// below check for known C library versions and conditions under which these
+// functions are declared by the C library.
+//
+// GNU libc 2.36 and newer declare c8rtomb() and mbrtoc8() in C++ modes if
+// __cpp_char8_t is defined or if C2X extensions are enabled. Determining
+// the latter depends on internal GNU libc details that are not appropriate
+// to depend on here, so any declarations present when __cpp_char8_t is not
+// defined are ignored.
+#  if _LIBCPP_GLIBC_PREREQ(2, 36) && defined(__cpp_char8_t)
+#    define _LIBCPP_HAS_C8RTOMB_MBRTOC8 1
+#  else
+#    define _LIBCPP_HAS_C8RTOMB_MBRTOC8 0
+#  endif
+
+// There are a handful of public standard library types that are intended to
+// support CTAD but don't need any explicit deduction guides to do so. This
+// macro is used to mark them as such, which suppresses the
+// '-Wctad-maybe-unsupported' compiler warning when CTAD is used in user code
+// with these classes.
+#  if _LIBCPP_STD_VER >= 17
+#    ifdef _LIBCPP_COMPILER_CLANG_BASED
+#      define _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(_ClassName)                                                              \
+        template <class... _Tag>                                                                                       \
+        [[maybe_unused]] _ClassName(typename _Tag::__allow_ctad...)->_ClassName<_Tag...>
+#    else
+#      define _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(ClassName)                                                               \
+        template <class... _Tag>                                                                                       \
+        ClassName(typename _Tag::__allow_ctad...)->ClassName<_Tag...>
+#    endif
+#  else
+#    define _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(_ClassName) static_assert(true, "")
+#  endif
+
+#  if defined(__OBJC__) && defined(_LIBCPP_APPLE_CLANG_VER)
+#    define _LIBCPP_WORKAROUND_OBJCXX_COMPILER_INTRINSICS
+#  endif
+
+#  define _PSTL_PRAGMA(x) _Pragma(#x)
+
+// Enable SIMD for compilers that support OpenMP 4.0
+#  if (defined(_OPENMP) && _OPENMP >= 201307)
+
+#    define _PSTL_UDR_PRESENT
+#    define _PSTL_PRAGMA_SIMD _PSTL_PRAGMA(omp simd)
+#    define _PSTL_PRAGMA_DECLARE_SIMD _PSTL_PRAGMA(omp declare simd)
+#    define _PSTL_PRAGMA_SIMD_REDUCTION(PRM) _PSTL_PRAGMA(omp simd reduction(PRM))
+#    define _PSTL_PRAGMA_SIMD_SCAN(PRM) _PSTL_PRAGMA(omp simd reduction(inscan, PRM))
+#    define _PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(PRM) _PSTL_PRAGMA(omp scan inclusive(PRM))
+#    define _PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(PRM) _PSTL_PRAGMA(omp scan exclusive(PRM))
+
+// Declaration of reduction functor, where
+// NAME - the name of the functor
+// OP - type of the callable object with the reduction operation
+// omp_in - refers to the local partial result
+// omp_out - refers to the final value of the combiner operator
+// omp_priv - refers to the private copy of the initial value
+// omp_orig - refers to the original variable to be reduced
+#    define _PSTL_PRAGMA_DECLARE_REDUCTION(NAME, OP)                                                                   \
+      _PSTL_PRAGMA(omp declare reduction(NAME:OP : omp_out(omp_in)) initializer(omp_priv = omp_orig))
+
+#  elif defined(_LIBCPP_COMPILER_CLANG_BASED)
+
+#    define _PSTL_PRAGMA_SIMD _Pragma("clang loop vectorize(enable) interleave(enable)")
+#    define _PSTL_PRAGMA_DECLARE_SIMD
+#    define _PSTL_PRAGMA_SIMD_REDUCTION(PRM) _Pragma("clang loop vectorize(enable) interleave(enable)")
+#    define _PSTL_PRAGMA_SIMD_SCAN(PRM) _Pragma("clang loop vectorize(enable) interleave(enable)")
+#    define _PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(PRM)
+#    define _PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(PRM)
+#    define _PSTL_PRAGMA_DECLARE_REDUCTION(NAME, OP)
+
+#  else // (defined(_OPENMP) && _OPENMP >= 201307)
+
+#    define _PSTL_PRAGMA_SIMD
+#    define _PSTL_PRAGMA_DECLARE_SIMD
+#    define _PSTL_PRAGMA_SIMD_REDUCTION(PRM)
+#    define _PSTL_PRAGMA_SIMD_SCAN(PRM)
+#    define _PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(PRM)
+#    define _PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(PRM)
+#    define _PSTL_PRAGMA_DECLARE_REDUCTION(NAME, OP)
+
+#  endif // (defined(_OPENMP) && _OPENMP >= 201307)
+
+#  define _PSTL_USE_NONTEMPORAL_STORES_IF_ALLOWED
+
+#endif // __cplusplus
+
+#endif // _LIBCPP___CONFIG