bug#23368: 25.0.92; xftfont.c has got a bug

[Masaru Nomiya]

Hello,

With Emacs 25.0.92, Emacs 25.0.93, and Emacs 25.1.50, Emacs start to
use 100% CPU.
That is, afetr I start Wanderlust(MUA) on Emacs, and try to open some
folders in it, Emacs starts to use 100% CPU, and unresposible.

I investigated the latest Emacs with git bisect.
As a result, I found that xftfont.c has got a bug as follows.


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masaru@linux-uw5l:/tmp/tes/emacs> git checkout emacs-25
Branch emacs-25 set up to track remote branch emacs-25 from origin.
Switched to a new branch 'emacs-25'

masaru@linux-uw5l:/tmp/tes/emacs> git bisect start

masaru@linux-uw5l:/tmp/tes/emacs> git bisect bad

masaru@linux-uw5l:/tmp/tes/emacs> git bisect good emacs-25.0.91
Bisecting: 182 revisions left to test after this (roughly 8 steps)
[04f5525fbb961f6006280be340ca0f03df9e80a7] Make '.' associative, for easier 
sexp navigation

masaru@linux-uw5l:/tmp/tes/emacs> ./autogen.sh

masaru@linux-uw5l:/tmp/tes/emacs> ./configure

masaru@linux-uw5l:/tmp/tes/emacs> make bootstrap -j10

test --  NG

masaru@linux-uw5l:/tmp/tes/emacs> make clean

masaru@linux-uw5l:/tmp/tes/emacs> git bisect bad
Bisecting: 90 revisions left to test after this (roughly 7 steps)
[06a872b71d6580e0699600844bb9526602437990] Fix redisplay on a TTY after 
'make-frame'
[...]
masaru@linux-uw5l:/tmp/tes/emacs> make bootstrap -j10

test  --  OK

masaru@linux-uw5l:/tmp/tes/emacs> make clean

masaru@linux-uw5l:/tmp/tes/emacs> git bisect good
Bisecting: 0 revisions left to test after this (roughly 1 step)
[ec10ef95cf2a5309ec7cb74f1383860a13daa546] * lisp/apropos.el 
(apropos-variable): Doc fix.  (Bug#22813).

masaru@linux-uw5l:/tmp/tes/emacs> make bootstrap -j10

test  --  NG

masaru@linux-uw5l:/tmp/tes/emacs> make clean

masaru@linux-uw5l:/tmp/tes/emacs> git bisect bad
Bisecting: 0 revisions left to test after this (roughly 0 steps)
[d2dd614716e34edb5891e58c029741cd6b32217d] Remove unneeded workaround in 
xftfont.c

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※ test = Start Emacs & Wanderlust, then try to open the folder in
Wanderlust. OK means "can open without any problem", NG means "Emacs
eat 100% CPU).

---
 Masaru Nomiya             mail-to: nomiya @ galaxy.dti.ne.jp