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/inttypes.h

@@ -48,6 +48,8 @@ typedef __UINT_LEAST64_TYPE__ uint_least64_t;
 #define __PRI128 "ll"
 #elif __SIZEOF_INTMAX__ == 16
 #define __PRI128 "j"
+#else
+#define __PRI128 "jj"
 #endif
 
 #if __SIZEOF_POINTER__ == __SIZEOF_INT__