bug#21981: request: dired: require dired-x by default

[Michael Hoffman]

On 11/23/2015 5:06 PM, John Wiegley wrote:
> > > > > > Glenn Morris <rgm@gnu.org> writes:
>
> > AFAIK we are still waiting for someone to
> >    [add] the remaining useful functionality of dired-x into dired and
> >    then [make] dired-x obsolete.
>
> I would prefer this also, rather than pulling in all of dired-x. Michael,
> would you like to review the parts of dired-x that should move over?

dired-x.el is divided into a number of sections for different features. 
I use these features myself:

;;; JUMP.
;;; OMITTING.
;;; GUESS SHELL COMMAND.

These features look useful:

;;; EXTENSION MARKING FUNCTIONS.
;;; RELATIVE SYMBOLIC LINKS.
;;; VISIT ALL MARKED FILES SIMULTANEOUSLY.

This is pretty esoteric. It may be worth having this in a separate file 
from dired.el since its use is disjoint from normal use of dired:

;;; VIRTUAL DIRED MODE.

These look obsolete to me:

;;; FIND FILE AT POINT.
;;; SMART SHELL.
;;; LOCAL VARIABLES FOR DIRED BUFFERS.

Within the miscellaneous section, the following might have some utility:

- dired-man
- dired-info
- dired-rmail

The following look obsolete:

- dired-vm
- dired-do-run-mail seems unnecessary without VM