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

third_party/libcxx/include/cstdio

+// -*- C++ -*-
+//===---------------------------- cstdio ----------------------------------===//
+//
+//                     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_CSTDIO
+#define _LIBCPP_CSTDIO
+
+/*
+    cstdio synopsis
+
+Macros:
+
+    BUFSIZ
+    EOF
+    FILENAME_MAX
+    FOPEN_MAX
+    L_tmpnam
+    NULL
+    SEEK_CUR
+    SEEK_END
+    SEEK_SET
+    TMP_MAX
+    _IOFBF
+    _IOLBF
+    _IONBF
+    stderr
+    stdin
+    stdout
+
+namespace std
+{
+
+Types:
+
+FILE
+fpos_t
+size_t
+
+int remove(const char* filename);
+int rename(const char* old, const char* new);
+FILE* tmpfile(void);
+char* tmpnam(char* s);
+int fclose(FILE* stream);
+int fflush(FILE* stream);
+FILE* fopen(const char* restrict filename, const char* restrict mode);
+FILE* freopen(const char* restrict filename, const char * restrict mode,
+              FILE * restrict stream);
+void setbuf(FILE* restrict stream, char* restrict buf);
+int setvbuf(FILE* restrict stream, char* restrict buf, int mode, size_t size);
+int fprintf(FILE* restrict stream, const char* restrict format, ...);
+int fscanf(FILE* restrict stream, const char * restrict format, ...);
+int printf(const char* restrict format, ...);
+int scanf(const char* restrict format, ...);
+int snprintf(char* restrict s, size_t n, const char* restrict format, ...);    // C99
+int sprintf(char* restrict s, const char* restrict format, ...);
+int sscanf(const char* restrict s, const char* restrict format, ...);
+int vfprintf(FILE* restrict stream, const char* restrict format, va_list arg);
+int vfscanf(FILE* restrict stream, const char* restrict format, va_list arg);  // C99
+int vprintf(const char* restrict format, va_list arg);
+int vscanf(const char* restrict format, va_list arg);                          // C99
+int vsnprintf(char* restrict s, size_t n, const char* restrict format,         // C99
+              va_list arg);
+int vsprintf(char* restrict s, const char* restrict format, va_list arg);
+int vsscanf(const char* restrict s, const char* restrict format, va_list arg); // C99
+int fgetc(FILE* stream);
+char* fgets(char* restrict s, int n, FILE* restrict stream);
+int fputc(int c, FILE* stream);
+int fputs(const char* restrict s, FILE* restrict stream);
+int getc(FILE* stream);
+int getchar(void);
+char* gets(char* s);  // removed in C++14
+int putc(int c, FILE* stream);
+int putchar(int c);
+int puts(const char* s);
+int ungetc(int c, FILE* stream);
+size_t fread(void* restrict ptr, size_t size, size_t nmemb,
+             FILE* restrict stream);
+size_t fwrite(const void* restrict ptr, size_t size, size_t nmemb,
+              FILE* restrict stream);
+int fgetpos(FILE* restrict stream, fpos_t* restrict pos);
+int fseek(FILE* stream, long offset, int whence);
+int fsetpos(FILE*stream, const fpos_t* pos);
+long ftell(FILE* stream);
+void rewind(FILE* stream);
+void clearerr(FILE* stream);
+int feof(FILE* stream);
+int ferror(FILE* stream);
+void perror(const char* s);
+
+}  // std
+*/
+
+#include <__config>
+#include <stdio.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+// snprintf
+#if defined(_LIBCPP_MSVCRT)
+#include "support/win32/support.h"
+#endif
+
+#ifdef getc
+inline _LIBCPP_INLINE_VISIBILITY int __libcpp_getc(FILE* __stream) {return getc(__stream);}
+#undef getc
+inline _LIBCPP_INLINE_VISIBILITY int getc(FILE* __stream) {return __libcpp_getc(__stream);}
+#endif  // getc
+
+#ifdef putc
+inline _LIBCPP_INLINE_VISIBILITY int __libcpp_putc(int __c, FILE* __stream) {return putc(__c, __stream);}
+#undef putc
+inline _LIBCPP_INLINE_VISIBILITY int putc(int __c, FILE* __stream) {return __libcpp_putc(__c, __stream);}
+#endif  // putc
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::FILE;
+using ::fpos_t;
+using ::size_t;
+
+using ::remove;
+using ::rename;
+using ::tmpfile;
+using ::tmpnam;
+using ::fclose;
+using ::fflush;
+using ::fopen;
+using ::freopen;
+using ::setbuf;
+using ::setvbuf;
+using ::fprintf;
+using ::fscanf;
+using ::printf;
+using ::scanf;
+using ::snprintf;
+using ::sprintf;
+using ::sscanf;
+#ifndef _LIBCPP_MSVCRT
+using ::vfprintf;
+using ::vfscanf;
+using ::vscanf;
+using ::vsscanf;
+#endif // _LIBCPP_MSVCRT
+using ::vprintf;
+using ::vsnprintf;
+using ::vsprintf;
+using ::fgetc;
+using ::fgets;
+using ::fputc;
+using ::fputs;
+using ::getc;
+using ::getchar;
+#if _LIBCPP_STD_VER <= 11
+using ::gets;
+#endif
+using ::putc;
+using ::putchar;
+using ::puts;
+using ::ungetc;
+using ::fread;
+using ::fwrite;
+using ::fgetpos;
+using ::fseek;
+using ::fsetpos;
+using ::ftell;
+using ::rewind;
+using ::clearerr;
+using ::feof;
+using ::ferror;
+using ::perror;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif  // _LIBCPP_CSTDIO