Ever wanted an `else` after a `for` to run if the loop had no iterations? Easy:

```c
#define for(...) for (int __for_iter = 0, __for_empty = true; __for_iter < 2; ++__for_iter) if (__for_iter == 1 && !__for_empty) {} else if (__for_iter == 0) for(__VA_ARGS__) if (__for_empty = false) {} else
```

https://godbolt.org/z/PYos4PddP