bug#19466: 25.0.50; xref-find-def doesn't find C functions

[Eli Zaretskii <eliz@gnu.org>]

Run "make TAGS" in the top-level directory, then:

 emacs -Q
 Click menu-bar->Edit->Go To->Set Tags File Name
 Navigate to src/TAGS and select it in the file selection dialog
 Click menu-bar->Edit->Go To->Find Definition
 Type "display_line RET" at the prompt
 => [No match]

But of course this function does exists and lives in xdisp.c.

The above does work if I invoke the same sequence from a buffer
visiting xdisp.c (or any other file from src/), but that sounds like
an inconvenience.  The old tags feature didn't require that.


In GNU Emacs 25.0.50.110 (i686-pc-mingw32)
 of 2014-12-29 on HOME-C4E4A596F7
Repository revision: ce1ebdf1ba8acc75e8f959f414652cdc87e76401
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --prefix=/d/usr --enable-checking=yes,glyphs 'CFLAGS=-O0
 -g3''

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY ACL GNUTLS LIBXML2 ZLIB

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1255

Major mode: Lisp Interaction

Minor modes in effect:
  diff-auto-refine-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
  line-number-mode: t

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Quit
Starting a new list of tags tables
Quit

Load-path shadows:
None found.

Features:
(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 help-fns mail-prsvr mail-utils thingatpt vc-git diff-mode
easymenu easy-mmode etags xref eieio byte-opt bytecomp byte-compile
cl-extra cconv eieio-core cl-loaddefs cl-lib ring time-date tooltip
eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel
dos-w32 ls-lisp disp-table w32-win w32-vars 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 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
w32notify w32 multi-tty emacs)

Memory information:
((conses 8 91533 8774)
 (symbols 32 19742 0)
 (miscs 32 43 119)
 (strings 16 17923 4127)
 (string-bytes 1 497284)
 (vectors 8 12420)
 (vector-slots 4 417644 3202)
 (floats 8 71 100)
 (intervals 28 247 31)
 (buffers 516 12))