Add libc++ and libc++abi to third-party.

third_party/libcxx/include/support/win32/support.h

+// -*- C++ -*-
+//===----------------------- support/win32/support.h ----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_WIN32_SUPPORT_H
+#define _LIBCPP_SUPPORT_WIN32_SUPPORT_H
+
+/*
+   Functions and constants used in libc++ that are missing from the Windows C library.
+  */
+
+#include <wchar.h>  // mbstate_t
+#include <cstdarg> // va_ macros
+#define swprintf _snwprintf
+#define vswprintf _vsnwprintf
+
+#ifndef NOMINMAX
+#define NOMINMAX
+#endif
+#include <Windows.h>
+
+extern "C" {
+
+int vasprintf( char **sptr, const char *__restrict fmt, va_list ap );
+int asprintf( char **sptr, const char *__restrict fmt, ...);
+size_t mbsnrtowcs( wchar_t *__restrict dst, const char **__restrict src,
+                   size_t nmc, size_t len, mbstate_t *__restrict ps );
+size_t wcsnrtombs( char *__restrict dst, const wchar_t **__restrict src,
+                   size_t nwc, size_t len, mbstate_t *__restrict ps );
+}
+
+#if defined(_LIBCPP_MSVCRT)
+#define snprintf _snprintf
+#include <xlocinfo.h>
+#define atoll _atoi64
+#define strtoll _strtoi64
+#define strtoull _strtoui64
+#define wcstoll _wcstoi64
+#define wcstoull _wcstoui64
+_LIBCPP_ALWAYS_INLINE float strtof( const char *nptr, char **endptr )
+{ return _Stof(nptr, endptr, 0); }
+_LIBCPP_ALWAYS_INLINE double strtod( const char *nptr, char **endptr )
+{ return _Stod(nptr, endptr, 0); }
+_LIBCPP_ALWAYS_INLINE long double strtold( const char *nptr, char **endptr )
+{ return _Stold(nptr, endptr, 0); }
+
+#define _Exit _exit
+
+#ifndef __clang__ // MSVC-based Clang also defines _MSC_VER
+#include <intrin.h>
+
+_LIBCPP_ALWAYS_INLINE int __builtin_popcount(unsigned int x) {
+   static const unsigned int m1 = 0x55555555; //binary: 0101...
+   static const unsigned int m2 = 0x33333333; //binary: 00110011..
+   static const unsigned int m4 = 0x0f0f0f0f; //binary:  4 zeros,  4 ones ...
+   static const unsigned int h01= 0x01010101; //the sum of 256 to the power of 0,1,2,3...
+   x -= (x >> 1) & m1;             //put count of each 2 bits into those 2 bits
+   x = (x & m2) + ((x >> 2) & m2); //put count of each 4 bits into those 4 bits
+   x = (x + (x >> 4)) & m4;        //put count of each 8 bits into those 8 bits
+   return (x * h01) >> 24;  //returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24)
+}
+
+_LIBCPP_ALWAYS_INLINE int __builtin_popcountl(unsigned long x) {
+  return __builtin_popcount(static_cast<int>(x));
+}
+
+_LIBCPP_ALWAYS_INLINE int __builtin_popcountll(unsigned long long x) {
+   static const unsigned long long m1  = 0x5555555555555555; //binary: 0101...
+   static const unsigned long long m2  = 0x3333333333333333; //binary: 00110011..
+   static const unsigned long long m4  = 0x0f0f0f0f0f0f0f0f; //binary:  4 zeros,  4 ones ...
+   static const unsigned long long h01 = 0x0101010101010101; //the sum of 256 to the power of 0,1,2,3...
+   x -= (x >> 1) & m1;             //put count of each 2 bits into those 2 bits
+   x = (x & m2) + ((x >> 2) & m2); //put count of each 4 bits into those 4 bits
+   x = (x + (x >> 4)) & m4;        //put count of each 8 bits into those 8 bits
+   return static_cast<int>((x * h01)>>56);  //returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24) + ...
+}
+
+_LIBCPP_ALWAYS_INLINE int __builtin_ctz( unsigned int x )
+{
+   DWORD r = 0;
+   _BitScanReverse(&r, x);
+   return static_cast<int>(r);
+}
+
+// sizeof(long) == sizeof(int) on Windows
+_LIBCPP_ALWAYS_INLINE int __builtin_ctzl( unsigned long x )
+{ return __builtin_ctz( static_cast<int>(x) ); }
+
+_LIBCPP_ALWAYS_INLINE int __builtin_ctzll( unsigned long long x )
+{
+    DWORD r = 0;
+    _BitScanReverse64(&r, x);
+    return static_cast<int>(r);
+}
+_LIBCPP_ALWAYS_INLINE int __builtin_clz( unsigned int x )
+{
+   DWORD r = 0;
+   _BitScanForward(&r, x);
+   return static_cast<int>(r);
+}
+// sizeof(long) == sizeof(int) on Windows
+_LIBCPP_ALWAYS_INLINE int __builtin_clzl( unsigned long x )
+{ return __builtin_clz( static_cast<int>(x) ); }
+_LIBCPP_ALWAYS_INLINE int __builtin_clzll( unsigned long long x )
+{
+    DWORD r = 0;
+    _BitScanForward64(&r, x);
+    return static_cast<int>(r);
+}
+#endif // !__clang__
+#endif // _LIBCPP_MSVCRT
+
+#endif // _LIBCPP_SUPPORT_WIN32_SUPPORT_H