[Bug d/95198] [D] extern(C) private final functions should use 'local' linker attribute

[witold.baryluk+gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95198

--- Comment #3 from Witold Baryluk <witold.baryluk+gcc at gmail dot com> ---
> The main example to demonstrate the current behaviour is correct would be the 
> following:

```
extern(C)
private final int f() {
  return 5;
}

auto pubf()() {
  return f();
}
```

I see, I guess you are right. I don't know how would one go to fix this to work
correctly with existing linkers and not break other code.

Thanks for clarifications.