Re: [PATCH v5 9/9] dir: introduce readdir_skip_dot_and_dotdot() helper

> From: Elijah Newren <newren@gmail.com>
> 
> Many places in the code were doing
>     while ((d = readdir(dir)) != NULL) {
>         if (is_dot_or_dotdot(d->d_name))
>             continue;
>         ...process d...
>     }
> Introduce a readdir_skip_dot_and_dotdot() helper to make that a one-liner:
>     while ((d = readdir_skip_dot_and_dotdot(dir)) != NULL) {
>         ...process d...
>     }
> 
> This helper particularly simplifies checks for empty directories.
> 
> Also use this helper in read_cached_dir() so that our statistics are
> consistent across platforms.  (In other words, read_cached_dir() should
> have been using is_dot_or_dotdot() and skipping such entries, but did
> not and left it to treat_path() to detect and mark such entries as
> path_none.)