Fails compilation on Linux (Ubuntu 24.04) & macOS ARM (15.2 - 24C101)

On Linux, the method from `<unistd.h>`:
```cpp
extern int pause()
```

conflicts with the method in nanothread, defined differently:
```
static void pause()
```

On macOS, there is only an incomplete type named `exception_ptr` in namespace `std`, forward declared but never completed. Furthermore, there is no member named `is_trivially_destructible` in namespace `std`. 