bug#33748: 27.0.50; harfbuzz branch fails to compile

[Eli Zaretskii]

The compilation fails with this error:

    CC       ftfont.o
  ftfont.c: In function ‘ftfont_shape_by_hb’:
  ftfont.c:2866:3: warning: implicit declaration of function 
‘hb_buffer_set_cluster_level’ [-Wimplicit-function-declaration]
     hb_buffer_set_cluster_level (hb_buffer, 
HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS);
     ^
  ftfont.c:2866:43: error: ‘HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS’ 
undeclared (first use in this function)
     hb_buffer_set_cluster_level (hb_buffer, 
HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS);
                                             ^
  ftfont.c:2866:43: note: each undeclared identifier is reported only once for 
each function it appears in
  make[1]: *** [ftfont.o] Error 1

The version of Harfbuzz I have on this machine is 0.9.27.  If this too old?  If 
so, what minimum version do I need to successfully build the branch?

(Note that this bug report is sent from Emacs built with a different 
configuration, for obvious reasons.)


In GNU Emacs 27.0.50 (build 35, x86_64-pc-linux-gnu, GTK+ Version 2.24.23)
 of 2018-12-09 built on fencepost.gnu.org
Repository revision: c2fdd50c3cb0b03d2414370c58c1aa2a6ec3311d
Repository branch: master
System Description: Trisquel GNU/Linux Belenos (7.0)

Recent messages:
Saving place in files enabled globally
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
 'configure --enable-checking=yes,glyphs --with-gif=no --with-tiff=no
 --with-jpeg=no --with-modules --enable-check-lisp-object-type
 'CFLAGS=-O0 -g3''

Configured features:
XPM PNG SOUND GSETTINGS GLIB NOTIFY INOTIFY ACL LIBSELINUX GNUTLS
LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS GTK2 X11
XDBE XIM MODULES THREADS

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

Major mode: Lisp Interaction

Minor modes in effect:
  display-time-mode: t
  show-paren-mode: t
  savehist-mode: t
  save-place-mode: t
  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
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t

Load-path shadows:
None found.

Features:
(shadow flyspell ispell emacsbug message rmc puny seq byte-opt gv
compile comint ansi-color ring bytecomp byte-compile cconv dired
dired-loaddefs format-spec rfc822 mml easymenu mml-sec password-cache
epa derived epg epg-config gnus-util rmail rmail-loaddefs time-date
mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
mailheader cl-loaddefs cl-lib sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils term/xterm xterm elec-pair server time
paren cus-start cus-load savehist saveplace mule-util 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 menu-bar rfn-eshadow
isearch timer select scroll-bar mouse jit-lock font-lock syntax
facemenu font-core term/tty-colors frame 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
minibuffer 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 inotify dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty
make-network-process emacs)

Memory information:
((conses 16 116491 9083)
 (symbols 48 21747 1)
 (strings 32 34083 1784)
 (string-bytes 1 922856)
 (vectors 16 13709)
 (vector-slots 8 470222 9078)
 (floats 8 59 312)
 (intervals 56 222 0)
 (buffers 992 10)
 (heap 1024 12212 901))