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.

tool/build/calculator.c

@@ -37,7 +37,7 @@
 #include "third_party/gdtoa/gdtoa.h"
 #include "third_party/getopt/getopt.h"
 
-#define INT     intmax_t
+#define INT     int128_t
 #define FLOAT   long double
 #define EPSILON 1e-16l
 
@@ -156,7 +156,7 @@ struct Value stack[128];
 int sp, comment, line, column, interactive;
 
 INT Popcnt(INT x) {
-  uintmax_t word = x;
+  uint128_t word = x;
   return popcnt(word >> 64) + popcnt(word);
 }
 
@@ -165,7 +165,7 @@ char *Repr(struct Value x) {
   if (x.t == kFloat) {
     g_xfmt_p(buf, &x.f, 16, sizeof(buf), 0);
   } else {
-    sprintf(buf, "%jd", x.i);
+    sprintf(buf, "%jjd", x.i);
   }
   return buf;
 }
@@ -449,7 +449,7 @@ bool ConsumeLiteral(const char *literal) {
   literal_ = literal;
   errno = 0;
   x.t = kInt;
-  x.i = strtoimax(literal, &e, 0);
+  x.i = strtoi128(literal, &e, 0);
   if (*e) {
     x.t = kFloat;
     x.f = strtod(literal, &e);