bug#15886: 24.3.50; Incorrect window-text-height with non-zero line-spacing

[Eli Zaretskii]

> From: Robert Dallas Gray <mail@robertdallasgray.com>
> Date: Wed, 13 Nov 2013 20:55:20 +0000
> Cc: 15886@debbugs.gnu.org
> 
> Well, it's not my library, but the reason it fails (in my setup, where I have 
> line-spacing set to 2), is that it tries to set the height of the minibuffer 
> using 'set-window-text-height' -- which, in my setup, sets the height 
> incorrectly (the bottom of the minibuffer is obscured). I note that 
> 'set-window-text-height' uses 'window-text-height' 

The argument passed to 'set-window-text-height' should be scaled by
the ratio of the values returned by 'frame-char-height' and
'default-line-height'.  (By default, this ratio is 1, but in your case
it will be different.)  The result of scaling should then be rounded
up to the nearest integer.