bug#58021: 29.0.50; Remove old font.c code

[Lars Ingebrigtsen <larsi@gnus.org>]

Eli Zaretskii <eliz@gnu.org> writes:

> Would it help if we move that to the end of the file?
>
> My primary motivation for leaving this is to try to attract someone to
> get involved in maintaining and developing font.c and fontset.c.
> We've all but lost our only expert on this, and leaving this part of
> Emacs without an active maintainer is bad for us.  I might even add a
> comment there that encourages people to finish implementation of at
> least some of that stuff, in the hope that this will bring on board
> someone capable and motivated.

Adding some commentary to it to explain what the purpose of the code is
(and why it hasn't been enabled) would be helpful, at least.

But the code's been around since 2006, apparently, so at some point it's
probably time to admit defeat.  But perhaps adding some text to explain
why it's there will entice somebody to look at it?  And then if that
hasn't happened at the 20 year anniversary of the code, we can revisit
this issue.