diff --git a/include/__config b/include/__config
index e431997..3b1c3a6 100644
--- a/include/__config
+++ b/include/__config
@@ -28,13 +28,35 @@
 #  define _LIBCPP_GCC_VER (__GNUC__ * 100 + __GNUC_MINOR__)
 #endif
 
+// Move outside #ifdef __cplusplus because this needs to work in both C and C++ headers.
+#if defined(__apple_build_version__)
+#  define _LIBCPP_COMPILER_CLANG_BASED
+#  define _LIBCPP_APPLE_CLANG_VER (__apple_build_version__ / 10000)
+#elif defined(__clang__)
+#  define _LIBCPP_COMPILER_CLANG
+#  define _LIBCPP_COMPILER_CLANG_BASED
+#  define _LIBCPP_CLANG_VER (__clang_major__ * 100 + __clang_minor__)
+#elif defined(__GNUC__)
+#  define _LIBCPP_COMPILER_GCC
+#elif defined(_MSC_VER)
+#  define _LIBCPP_COMPILER_MSVC
+
+#  if _MSVC_LANG == 201705L
+#    define _LIBCPP_STD_VER 20
+#  elif _MSVC_LANG == 201703L
+#    define _LIBCPP_STD_VER 17
+#  else
+#    define _LIBCPP_STD_VER 14
+#  endif
+#endif
+
 #ifdef __cplusplus
 
 // Warn if a compiler version is used that is not supported anymore
 // LLVM RELEASE Update the minimum compiler versions
 #  if defined(_LIBCPP_CLANG_VER)
 #    if _LIBCPP_CLANG_VER < 1500
-#      warning "Libc++ only supports Clang 15 and later"
+// we temporary allow old clang-s #      warning "Libc++ only supports Clang 15 and later"
 #    endif
 #  elif defined(_LIBCPP_APPLE_CLANG_VER)
 #    if _LIBCPP_APPLE_CLANG_VER < 1500
@@ -87,7 +109,7 @@
 #    define _LIBCPP_OBJECT_FORMAT_ELF 1
 #  elif defined(__MACH__)
 #    define _LIBCPP_OBJECT_FORMAT_MACHO 1
-#  elif defined(_WIN32)
+#  elif defined(_WIN32) || defined(__CYGWIN__)
 #    define _LIBCPP_OBJECT_FORMAT_COFF 1
 #  elif defined(__wasm__)
 #    define _LIBCPP_OBJECT_FORMAT_WASM 1
@@ -772,7 +794,7 @@ typedef __char32_t char32_t;
 // TODO: We provide a escape hatch with _LIBCPP_NO_ABI_TAG for folks who want to avoid increasing
 //       the length of symbols with an ABI tag. In practice, we should remove the escape hatch and
 //       use compression mangling instead, see https://github.com/itanium-cxx-abi/cxx-abi/issues/70.
-#  ifndef _LIBCPP_NO_ABI_TAG
+#  if !defined(_LIBCPP_NO_ABI_TAG) && !defined(__CUDACC__)
 #    define _LIBCPP_HIDE_FROM_ABI                                                                                      \
       _LIBCPP_HIDDEN _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION                                                       \
           __attribute__((__abi_tag__(_LIBCPP_TOSTRING(_LIBCPP_VERSIONED_IDENTIFIER))))
@@ -1075,7 +1097,8 @@ __sanitizer_verify_double_ended_contiguous_container(const void*, const void*, c
         defined(__APPLE__) ||                                                                                          \
         defined(__MVS__) ||                                                                                            \
         defined(_AIX) ||                                                                                               \
-        defined(__EMSCRIPTEN__)
+        defined(__EMSCRIPTEN__) ||                                                                                     \
+        defined(__CYGWIN__)
 // clang-format on
 #      define _LIBCPP_HAS_THREAD_API_PTHREAD
 #    elif defined(__Fuchsia__)
@@ -1211,6 +1234,10 @@ __sanitizer_verify_double_ended_contiguous_container(const void*, const void*, c
 #    define _LIBCPP_CONSTINIT
 #  endif
 
+#  if !__has_builtin(__builtin_is_constant_evaluated) || (defined(_LIBCPP_COMPILER_GCC) && _GNUC_VER < 900) || __CUDACC_VER_MAJOR__ == 10
+#    define _LIBCPP_HAS_NO_BUILTIN_IS_CONSTANT_EVALUATED
+#  endif
+
 #  if __has_attribute(__diagnose_if__) && !defined(_LIBCPP_DISABLE_ADDITIONAL_DIAGNOSTICS)
 #    define _LIBCPP_DIAGNOSE_WARNING(...) __attribute__((__diagnose_if__(__VA_ARGS__, "warning")))
 #  else
@@ -1232,6 +1259,12 @@ __sanitizer_verify_double_ended_contiguous_container(const void*, const void*, c
 #    define _LIBCPP_LIFETIMEBOUND
 #  endif
 
+#  if defined(_LIBCPP_COMPILER_CLANG_BASED)
+#    define _LIBCPP_REINITIALIZES_OBJECT [[clang::reinitializes]]
+#  else
+#    define _LIBCPP_REINITIALIZES_OBJECT
+#  endif
+
 #  if __has_attribute(__nodebug__)
 #    define _LIBCPP_NODEBUG __attribute__((__nodebug__))
 #  else
@@ -1289,6 +1322,10 @@ __sanitizer_verify_double_ended_contiguous_container(const void*, const void*, c
 #    define _LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS
 #  endif // _LIBCPP_ENABLE_CXX20_REMOVED_FEATURES
 
+// Yandex-specific: We build our own libc++, so it has everything available
+#  define _LIBCPP_DISABLE_AVAILABILITY
+// End of Yandex-specific
+
 // clang-format off
 #  define _LIBCPP_PUSH_MACROS _Pragma("push_macro(\"min\")") _Pragma("push_macro(\"max\")") _Pragma("push_macro(\"refresh()\")") _Pragma("push_macro(\"move(int, int)\")") _Pragma("push_macro(\"erase()\")")
 #  define _LIBCPP_POP_MACROS _Pragma("pop_macro(\"min\")") _Pragma("pop_macro(\"max\")") _Pragma("pop_macro(\"refresh()\")") _Pragma("pop_macro(\"move(int, int)\")") _Pragma("pop_macro(\"erase()\")")