Yeah, please try to stick to the original header as close as possible. We're having a hard time with some modules because of using different type definitions, e.g. core.sys.posix.sys.stat.
In general translate `ifdef` with `version` instead of using a type that works in both branches.

So here it's this, right?

```d
version (Win64)
    alias INT_PTR function() FARPROC;
else
    alias int function() FARPROC;
```