bug#2275: ntemacs 23.0.90: Glyph overlapping.

[Jason Rumney]

Kevin Yu wrote:
> As the attached picture shows.
>
> to reproduce this bug:
>
>     1: C-h i
>     2: select the "The Info Directory" by mouse
>     3: repeat step 2
>   

I can't reproduce this, but suspect the problem is that the face for 
Info headings explicitly specifies "Helv", which on Windows is by 
default substituted by "MS Sans Serif". If a real "Helv" font is 
installed, this causes confusion in the font APIs, with some calls 
getting results for the substituted font, and others getting the real 
one. The fix for bug#2219 may have fixed this already, but I added a 
further explicit check for "Helv" substitutions since it is a well-known 
substitution, and in some installations may be substituted by a truetype 
font, which won't be caught by the current test.

Please let me know whether you can still reproduce the bug in a fresh 
checkout.