bug#12600: 24.2.50; linum-mode: line numbers in fringe do not refresh when resizing frame

[martin rudalics]

> I don't think we can trust redisplay to have updated the screen before
> the hooks used by linum-mode run.

So what does

  If UPDATE is non-nil, compute the up-to-date position
  if it isn't already recorded.

in the doc-string of `window-end' really stand for?

martin