bug#3366: 23.0.94; doc of split-window-preferred-function, display-buffer, etc.

[martin rudalics]

> No, I'm talking about code, not a broad user preference setting. Code that
> wants, for example, to work with various releases.

Such code should get fixed in order to not rely on the heuristics of any
release.  With Emacs 23 you can bind `window-size-fixed' around calls to
`display-buffer' in order to avoid that a particular window gets split.
With Emacs 22 `display-buffer' usually throws an error when the largest
or LRU window has fixed size.

martin