bug#20628: 25.0.50; Incorrect line height for some fonts

[Eli Zaretskii]

> Date: Fri, 22 May 2015 15:09:11 -0400
> From: Clément Pit--Claudel
>  <clement.pitclaudel@live.com>
> CC: 20628@debbugs.gnu.org
> 
> If we don't find what causes this strange ascent computation, and as a 
> slightly more general approach that the patch above, what about including an 
> ascent-override-alist at the Lisp level, which could by default contain 
> ("Latin Modern Math" . 0) and maybe other entries for a number of other Latin 
> Modern variants?
> 

I'd rather tell users how to avoid these fonts entirely.  Making such
ad-hoc changes to font metrics sounds too much for my palate, unless
some expert tells us this is how everybody else does it.