bug#16721: 24.3.50; can not use ext font anymore

[Ivan Kanis]

1) emacs -Q
2) eval the following in *scratch*

(set-fontset-font "fontset-default" nil
  "xft:-unknown-Symbola-normal-normal-semi-condensed-*-20-*-*-*-*-0-iso10646-1")

I expect a return of nil. I get an error "Invalid font name".

On Debian the package ttf-ancient-fonts contains the font.

In GNU Emacs 24.3.50.1 (i686-pc-linux-gnu, GTK+ Version 2.24.20)
 of 2014-02-08 on tao.kanis.fr
Repository revision: 116348 
michael.albinus@gmx.de-20140208133515-mgy8agwqq4nc6bfb
Windowing system distributor `The X.Org Foundation', version 11.0.11403000
System Description:     Ubuntu 13.10

Configured using:
 `configure --prefix=/home/ivan/emacs-bzr --without-compress-install
 'CFLAGS=-g -DSYSTEM_PURESIZE_EXTRA=1000000''

Important settings:
  value of $LANG: en_US.UTF8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-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

Recent input:
M-x r e p o r t - b u g <return>

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

Load-path shadows:
None found.

Features:
(shadow sort hashcash gnus-util mail-extr emacsbug message format-spec
rfc822 mml easymenu mml-sec mm-decode mm-bodies mm-encode mail-parse
rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045
ietf-drums mm-util help-fns mail-prsvr mail-utils time-date tooltip
electric uniquify ediff-hook vc-hooks lisp-float-type mwheel x-win x-dnd
tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment
lisp-mode prog-mode register page menu-bar rfn-eshadow timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame cham
georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese hebrew greek romanian slovak czech european ethiopic
indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple
abbrev minibuffer 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 make-network-process
dbusbind gfilenotify dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty emacs)