The previous implementation was inconsistent, sometimes it would
inherit the name of the parent folder of the current directory.

Other scenarios i encountered were:
1. Yield a empty search result, and try to edit. It would seemingly
   randomly select a file or folder
2. What would happen in a root path without any files residing?

* Start implementation on show list of files as input

* Remove tmp dir on exit, set global flag

* Bug fixes and improvements

* Follow symlinks when in list paths mode

* Fix bugs

* Add flag check

* Add message for invalid paths and style fixes

* Change the message

* Addressing review comments

* Handle errno being set

* Fix CI break

* Decreased startup memory usage and removed loops

* Fix CI break

The NNN_PIPE file gets deleted after spawning a child in NOWAIT mode. Steps:
- open `nnn` with option `-x`
- press `;o` (custom binding) to open fzopen plugin
- press `^J` to select a file; it will spawn plugin `.cbcp` in NOWAIT mode
- when the intermediate child quits, the NNN_PIPE of parent is also deleted

The following changes are made:

- STDOUT and STDIN are redirected to /dev/null when spawning rclone
  rclone blocks and also shows error/warning messages. nnn needs to spawn
  rclone and return without waiting. To avoid the rclone messages from
  corrupting the screen nnn makes the child silent.
  Note: sshfs returns after mount with a proper error code
- prompt only if both sshfs and rclone are installed

* Fallbacks for absent NAME_MAX and PATH_MAX

Certainly NAME_MAX isn't guaranteed to exist and on (some versions of?)
Illumos and SmartOS it doesn't, so provide some reasonably accommodating
fallbacks.

* Smaller limits

* Remove now redundant PATH_MAX definition for Hurd