Enhance dired-dwim-target to work with intervening non-Dired buffer

[Andrew Scott]

In GNU Emacs 21.1.2 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2001-10-23 on chlx022
configured using `configure  --prefix=/stor/garray/linux'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: C
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

This is an enhancement request (additional functionality).
I would like the dired-aux functions that observe (setq
dired-dwim-target) to be able to tolerate intervening non-Dired
buffers in the same frame. For example, if the Frame has:

+---------------------------------+
| Dired buffer A                  |
+---------------------------------+
| Non-Dired buffer (e.g. *shell*) |
+---------------------------------+
| Dired buffer B                  |
+---------------------------------+

then invoking dired-do-copy in Dired Buffer A would prompt me with the
target directory associated with the next Dired Buffer (i.e. Dired
Buffer B).

Thank you,
Andy Scott