Merge pull request #230 from jeremyevans/patch-1

Ensure 16-byte alignment for amd64 coroutine stack

libs/coroutine/source/Coro.c

@@ -599,7 +599,7 @@ void Coro_setup(Coro *self, void *arg)
 			if (64 > (- sav[i] + (uintptr_t)&i))
 				break;
 		assert(i < sz);
-		sav[i] = stackend - sizeof(uintptr_t) - 128;
+		sav[i] = stackend - sizeof(uintptr_t)*2 - 128;
 	}
 }