Import C++ Standard Template Library

You can now use the hardest fastest and most dangerous language there is
with Cosmopolitan. So far about 75% of LLVM libcxx has been added. A few
breaking changes needed to be made to help this go smoothly.

- Rename nothrow to dontthrow
- Rename nodiscard to dontdiscard
- Add some libm functions, e.g. lgamma, nan, etc.
- Change intmax_t from int128 to int64 like everything else
- Introduce %jjd formatting directive for int128_t
- Introduce strtoi128(), strtou128(), etc.
- Rename bsrmax() to bsr128()

Some of the templates that should be working currently are std::vector,
std::string, std::map, std::set, std::deque, etc.

third_party/libcxx/stdlib.h

@@ -0,0 +1,103 @@
+// -*- C++ -*-
+//===--------------------------- stdlib.h ---------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#if defined(__need_malloc_and_calloc) || defined(_LIBCPP_STDLIB_INCLUDE_NEXT)
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#if defined(_LIBCPP_STDLIB_INCLUDE_NEXT)
+#undef _LIBCPP_STDLIB_INCLUDE_NEXT
+#endif
+
+#include "libc/isystem/stdlib.h"
+
+#elif !defined(_LIBCPP_STDLIB_H)
+#define _LIBCPP_STDLIB_H
+
+/*
+    stdlib.h synopsis
+
+Macros:
+
+    EXIT_FAILURE
+    EXIT_SUCCESS
+    MB_CUR_MAX
+    NULL
+    RAND_MAX
+
+Types:
+
+    size_t
+    div_t
+    ldiv_t
+    lldiv_t                                                               // C99
+
+double    atof (const char* nptr);
+int       atoi (const char* nptr);
+long      atol (const char* nptr);
+long long atoll(const char* nptr);                                        // C99
+double             strtod  (const char* restrict nptr, char** restrict endptr);
+float              strtof  (const char* restrict nptr, char** restrict endptr); // C99
+long double        strtold (const char* restrict nptr, char** restrict endptr); // C99
+long               strtol  (const char* restrict nptr, char** restrict endptr, int base);
+long long          strtoll (const char* restrict nptr, char** restrict endptr, int base); // C99
+unsigned long      strtoul (const char* restrict nptr, char** restrict endptr, int base);
+unsigned long long strtoull(const char* restrict nptr, char** restrict endptr, int base); // C99
+int rand(void);
+void srand(unsigned int seed);
+void* calloc(size_t nmemb, size_t size);
+void free(void* ptr);
+void* malloc(size_t size);
+void* realloc(void* ptr, size_t size);
+void abort(void);
+int atexit(void (*func)(void));
+void exit(int status);
+void _Exit(int status);
+char* getenv(const char* name);
+int system(const char* string);
+void* bsearch(const void* key, const void* base, size_t nmemb, size_t size,
+              int (*compar)(const void *, const void *));
+void qsort(void* base, size_t nmemb, size_t size,
+           int (*compar)(const void *, const void *));
+int         abs(      int j);
+long        abs(     long j);
+long long   abs(long long j);                                             // C++0X
+long       labs(     long j);
+long long llabs(long long j);                                             // C99
+div_t     div(      int numer,       int denom);
+ldiv_t    div(     long numer,      long denom);
+lldiv_t   div(long long numer, long long denom);                          // C++0X
+ldiv_t   ldiv(     long numer,      long denom);
+lldiv_t lldiv(long long numer, long long denom);                          // C99
+int mblen(const char* s, size_t n);
+int mbtowc(wchar_t* restrict pwc, const char* restrict s, size_t n);
+int wctomb(char* s, wchar_t wchar);
+size_t mbstowcs(wchar_t* restrict pwcs, const char* restrict s, size_t n);
+size_t wcstombs(char* restrict s, const wchar_t* restrict pwcs, size_t n);
+int at_quick_exit(void (*func)(void))                                     // C++11
+void quick_exit(int status);                                              // C++11
+void *aligned_alloc(size_t alignment, size_t size);                       // C11
+
+*/
+
+#include "third_party/libcxx/__config"
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#include "libc/isystem/stdlib.h"
+
+#ifdef __cplusplus
+#include "third_party/libcxx/math.h"
+#endif // __cplusplus
+
+#endif // _LIBCPP_STDLIB_H