Rebecca Turner a6c8cd6e85 Fix man completions on macOS with symlinked manpath
When `manpath` prints a symlink to a directory, `/usr/libexec/makewhatis`
ignores the entire directory:

```
$ /usr/libexec/makewhatis -o /tmp/whatis \
    (/usr/bin/manpath | string split :)
makewhatis: /Users/wiggles/.nix-profile/share/man: Not a directory
```

This means that the built-in `man` completions will not index any commands in
these directories.

If we pass the directories to `readlink -f` first, `makewhatis` correctly
indexes the `man` pages.

```
$ /usr/libexec/makewhatis -o /tmp/whatis \
    (/usr/bin/manpath | string split : | xargs readlink -f)
```
2024-09-14 13:38:33 -07:00
..
2024-09-13 09:59:56 +02:00