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.

libc/fmt/wcstoull.c

@@ -0,0 +1,53 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/errno.h"
+#include "libc/fmt/conv.h"
+#include "libc/fmt/strtol.internal.h"
+#include "libc/str/str.h"
+
+/**
+ * Decodes unsigned long long integer from wide string.
+ *
+ * @param s is a non-null nul-terminated string
+ * @param endptr if non-null will always receive a pointer to the char
+ *     following the last one this function processed, which is usually
+ *     the NUL byte, or in the case of invalid strings, would point to
+ *     the first invalid character
+ * @param base can be anywhere between [2,36] or 0 to auto-detect based
+ *     on the the prefixes 0 (octal), 0x (hexadecimal), 0b (binary), or
+ *     decimal (base 10) by default
+ * @return decoded integer mod 2⁶⁴ negated if leading `-`
+ */
+unsigned long long wcstoull(const wchar_t *s, wchar_t **endptr, int base) {
+  char t = 0;
+  int d, c = *s;
+  unsigned long long x = 0;
+  CONSUME_SPACES(s, c);
+  GET_SIGN(s, c, d);
+  GET_RADIX(s, c, base);
+  if ((c = kBase36[c & 255]) && --c < base) {
+    t |= 1;
+    do {
+      x *= base;
+      x += c;
+    } while ((c = kBase36[*++s & 255]) && --c < base);
+  }
+  if (t && endptr) *endptr = s;
+  return d > 0 ? x : -x;
+}