bug#9949: 24.0.91; window-width function does not take text-scale-mode-amount into account

[martin rudalics]

> The window-width function does not take text scale adjustments
> into account.  This breaks code such as
> http://www.emacswiki.org/emacs/ErcFilling#toc2 which is meant to
> insert timestamps aligned to the right edge of the window.

Recipe by courtesy of Johan Bockgård:

(insert (propertize
             " " 'display
             '(space :align-to (- text 8))) "#123456")

martin