bug#34663: remove ftx font backend

[Robert Pluim]

>>>>> On Tue, 07 Jan 2020 05:34:42 +0200, Eli Zaretskii <eliz@gnu.org> said:

    >> From: Robert Pluim <rpluim@gmail.com>
    >> Cc: Stefan Kangas <stefan@marxist.se>,  34663@debbugs.gnu.org
    >> Date: Tue, 07 Jan 2020 00:05:36 +0100
    >> 
    Eli> . please add a NEWS entry about ftx's removal (in the "Installation
    Eli> Changes" section)
    Eli> . please add a NEWS entry on the emacs-27 branch saying that this
    Eli> font backend is deprecated and will be removed
    >> 
    >> Can we do something similar for XFT (and flip --with-cairo to
    >> enabled)?

    Eli> I understand about enabling Cairo, but what exactly are you proposing
    Eli> to do with XFT?

Add an entry to NEWS on master that itʼs deprecated and will be
removed, and add verbiage to configure telling people to install cairo
development packages if XFT is detected. That means weʼd remove XFT in
emacs-29.

Robert