bug#22207: emacs-25 mishandles info code text on Fedora 23

[Paul Eggert]

When I use emacs-25 to view the Elisp manual on Fedora 23 x86-64, Emacs 
mishandles the font for code: code is displayed in a considerably 
smaller font, making the manual harder to read and looking a bit like a 
ransom note. A sample is attached. I am using 'emacs -Q' to read the 
info file. If I view the same (i.e., the emacs-25) info file with Emacs 
24.5 as bundled with Fedora, the display looks fine, with the same 
fixed-width font used for all text.


In GNU Emacs 25.0.50.8 (x86_64-unknown-linux-gnu, GTK+ Version 3.18.6)
 of 2015-12-17
Repository revision: 1b5630eb47d3f4bade09708c958ab006b83b3fc0
Windowing system distributor 'Fedora Project', version 11.0.11800000
Configured using:
 'configure --enable-gcc-warnings'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS
NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Info

Minor modes in effect:
  shell-dirtrack-mode: t
  tooltip-mode: t
  global-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
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
Checking 24 files in /home/eggert/src/gnu/emacs/my/lisp/cedet...
Checking 57 files in /home/eggert/src/gnu/emacs/my/lisp/calendar...
Checking 87 files in /home/eggert/src/gnu/emacs/my/lisp/calc...
Checking 122 files in /home/eggert/src/gnu/emacs/my/lisp/obsolete...
Checking for load-path shadows...done
You can run the command ‘report-emacs-bug’ with M-x r-em RET
Checking for load-path shadows...done
Auto-saving...done
Quit [3 times]
C-M-g is undefined

Load-path shadows:
None found.

Features:
(pp shadow sort gnus-util mail-extr emacsbug message dired format-spec
rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils help-fns help-mode cl-loaddefs pcase
cl-lib shell pcomplete comint ansi-color ring info easymenu time-date
mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel x-win term/common-win x-dnd tool-bar dnd fontset
image regexp-opt fringe tabulated-list newcomment elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow timer select scroll-bar
mouse jit-lock font-lock syntax facemenu font-core 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 charscript case-table epa-hook
jka-cmpr-hook help simple abbrev 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 dbusbind 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 123742 15169)
 (symbols 48 19951 3)
 (miscs 40 89 292)
 (strings 32 23330 7050)
 (string-bytes 1 657185)
 (vectors 16 12693)
 (vector-slots 8 432940 13272)
 (floats 8 150 162)
 (intervals 56 4895 83)
 (buffers 976 16)
 (heap 1024 38893 944))

Screenshot from 2015-12-18 10-21-19.png
Description: PNG image