bug#22207: emacs-25 mishandles info code text on Fedora 23

[Eli Zaretskii <eliz@gnu.org>]

> From: Wolfgang Jenkner <wjenkner@inode.at>
> Cc: Glenn Morris <rgm@gnu.org>,  eggert@cs.ucla.edu,  22207@debbugs.gnu.org
> Date: Sat, 19 Dec 2015 15:21:10 +0100
> 
> On Fri, Dec 18 2015, Eli Zaretskii wrote:
> 
> >> fc-match "Monospace"
> >
> > How will that help?  Someone, somewhere will still dislike the result.
> 
> Mono(space) is a fontconfig alias, it's explicitly selected in
> a configuration file[*] and users are supposed to override it if they don't
> like it.

That means an even more complex mess: suppose Emacs will use some
fixed-pitch font from that alias, and the user doesn't like it -- now
the user will have to be familiar not only with font specs for
customizing faces, but also with the fontconfig customizations and
configuration files.  Doesn't strike me as a particularly
user-friendly feature.

Once again, I suggest a single binary defcustom that could be used to
disable use of a special face for code typeface.  We could (and
probably should) tell in NEWS how to get back the old behavior by
customizing that variable.  This is by far simpler than silently
assuming users will futz with their font setups.