Re: Infrastructural complexity.

[Richard Stallman]

    I doubt Richard deliberately used window configurations in
    `adjust-window-trailing-edge'.  Unless we can get `enlarge-window' DTRT
    in all cases (which seems a rather challenging task IMHO) saving window
    configurations is an effective albeit somewhat expensive way to handle
    this and similar behaviors.

I used window configurations as a simple and reliable way to make
sure it would not delete the window.  If someone wants to make it use
a different and faster method, I have nothing against it.

Note that `adjust-window-trailing-edge' is conceptually a lower level
and more predictable operation than `enlarge-window'.  One could
imagine rewriting `enlarge-window' in Lisp and making it use
`adjust-window-trailing-edge'.