bug#6204: vc-dir always splits the frame

[martin rudalics]

> If the buffer names are sufficiently regular and unique,
> special-display-regexps can already provide the needed customizability
> without any need for a new option.

What about cases where buffer names are not regular and unique?

Also, I'm afraid we currently ignore the fact that most users are simple
not prepared to invest their time in studying the semantics of an option
like `special-display-regexps'.

Finally, this and `special-display-buffer-names' are user options and we
again have the problem that an application binding that (or, worse,
permanently adding its buffer names to it) may conflict with users
expectations (or, worse, getting her the CHANGED outside Customize
annyoances).

martin