Emacs won't build with old versions of fontconfig

[Andrei Kuznetsov]

I was unable to build Emacs 27.2 on a system with some old version
(2.5.0) of fontconfig without applying the following patch:

diff -u a/emacs-27.2/src/xftfont.c b/emacs-27.2/src/xftfont.c
--- a/emacs-27.2/src/xftfont.c
+++ b/emacs-27.2/src/xftfont.c
@@ -588,8 +588,10 @@
r1 = FcPatternGetInteger (pat, FC_HINT_STYLE, 0, &i1);
r2 = FcPatternGetInteger (oldpat, FC_HINT_STYLE, 0, &i2);
if (r1 != r2 || i1 != i2) goto out;
+#ifdef FC_LCD_FILTER
r1 = FcPatternGetInteger (pat, FC_LCD_FILTER, 0, &i1);
r2 = FcPatternGetInteger (oldpat, FC_LCD_FILTER, 0, &i2);
+#endif
if (r1 != r2 || i1 != i2) goto out;
r1 = FcPatternGetInteger (pat, FC_RGBA, 0, &i1);
r2 = FcPatternGetInteger (oldpat, FC_RGBA, 0, &i2);

Diff finished. Sat Jul 24 14:26:32 2021

The system on which the bug was discovered runs Fedora Core 9, but it
should be reproducible by building Emacs with Xft on a system with
fontconfig older than 2.6.0 (and possibly newer -- I am not sure on
that).

In GNU Emacs 27.2 (build 1, powerpc-unknown-linux-gnu, X toolkit, Xaw3d scroll bars)
of 2021-07-24 built on Po-Lus-iBook-G4.lan
Windowing system distributor 'The X.Org Foundation', version 11.0.12101001
System Description: Fedora release 9 (Sulphur)

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
'configure --prefix=/usr/local --with-gnutls=no'

Configured features:
XAW3D XPM JPEG TIFF GIF PNG RSVG SOUND GPM DBUS GCONF GLIB ACL
LIBSELINUX LIBXML2 FREETYPE XFT ZLIB TOOLKIT_SCROLL_BARS LUCID X11 XDBE
XIM MODULES THREADS PDUMPER

Important settings:
value of $LANG: en_GB.UTF-8
locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
tooltip-mode: t
global-eldoc-mode: t
eldoc-mode: t
electric-indent-mode: t
mouse-wheel-mode: t
tool-bar-mode: t
menu-bar-mode: t
file-name-shadow-mode: t
global-font-lock-mode: t
font-lock-mode: t
blink-cursor-mode: t
auto-composition-mode: t
auto-encryption-mode: t
auto-compression-mode: t
line-number-mode: t
transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
format-spec rfc822 mml easymenu mml-sec password-cache epa derived epg
epg-config gnus-util rmail rmail-loaddefs text-property-search seq
byte-opt gv bytecomp byte-compile cconv mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils time-date subr-x
cl-loaddefs cl-lib tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel term/x-win x-win term/common-win x-dnd tool-bar
dnd fontset image regexp-opt fringe tabulated-list replace newcomment
text-mode elisp-mode lisp-mode prog-mode register page tab-bar menu-bar
rfn-eshadow isearch timer select scroll-bar mouse jit-lock font-lock
syntax facemenu font-core term/tty-colors frame minibuffer cl-generic
cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech
european ethiopic indian cyrillic chinese composite charscript charprop
case-table epa-hook jka-cmpr-hook help simple abbrev obarray
cl-preloaded nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote threads dbusbind
dynamic-setting system-font-setting font-render-setting x-toolkit x
multi-tty make-network-process emacs)

Memory information:
((conses 8 44357 8801)
(symbols 24 5958 1)
(strings 16 16066 1889)
(string-bytes 1 512783)
(vectors 8 9285)
(vector-slots 4 137016 13736)
(floats 8 21 50)
(intervals 28 202 7)
(buffers 576 11)
(heap 1024 3934 455))