bug#63390: 29.0.90; c-ts-mode fails to recognize functions in xterm.c

[Eli Zaretskii]

To reproduce:

  emacs -Q
  M-x load-library RET c-ts-mode RET
  C-x C-f src/xterm.c
  C-u 8290 M-g g

Observe that the name of the function x_draw_glyph_string_foreground
is not fontified in font-lock-function-name-face, but in the default
face.

Starting treesit-explore-mode seems to indicate that tree-sitter
interprets this as a function declaration, not a function definition:

  (function_declarator declarator: (identifier)
   parameters: 
    (parameter_list (
     (parameter_declaration
      type: (struct_specifier struct name: (type_identifier))
      declarator: (pointer_declarator * declarator: (identifier)))
     )))

Same with the next function, x_draw_composite_glyph_string_foreground.
But the function after that, x_draw_glyphless_glyph_string_foreground,
is again recognized as function definition.  I wonder if the
preprocessor conditionals around there have something to do with that.

Btw, function declarations in a header file are recognized as such,
but the names of the functions there are still correctly fontified.

In GNU Emacs 29.0.90 (build 88, i686-pc-mingw32) of 2023-05-09 built on
 HOME-C4E4A596F7
Repository revision: 387ddc0ccc1b21f612b9106bafec63170ede30e6
Repository branch: emacs-29
Windowing system distributor 'Microsoft Corp.', version 5.1.2600
System Description: Microsoft Windows XP Service Pack 3 (v5.1.0.2600)

Configured using:
 'configure -C --prefix=/d/usr --with-wide-int
 --enable-checking=yes,glyphs 'CFLAGS=-O0 -gdwarf-4 -g3''

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG JSON LCMS2 LIBXML2 MODULES NOTIFY
W32NOTIFY PDUMPER PNG RSVG SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XPM ZLIB

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

Major mode: C/*

Minor modes in effect:
  bug-reference-prog-mode: t
  treesit-explore-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  show-paren-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
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
epg-config gnus-util text-property-search time-date subr-x mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils vc-git
diff-mode easy-mmode vc-dispatcher bug-reference byte-opt gv bytecomp
byte-compile c-ts-mode c-ts-common treesit cl-seq thingatpt cl-loaddefs
cl-lib find-func rmc iso-transl tooltip cconv eldoc paren electric
uniquify ediff-hook vc-hooks lisp-float-type elisp-mode mwheel dos-w32
ls-lisp disp-table term/w32-win w32-win w32-vars term/common-win
tool-bar dnd fontset image regexp-opt fringe tabulated-list replace
newcomment text-mode lisp-mode prog-mode register page tab-bar menu-bar
rfn-eshadow isearch easymenu timer select scroll-bar mouse jit-lock
font-lock syntax font-core term/tty-colors frame minibuffer nadvice seq
simple cl-generic indonesian philippine 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 emoji-zwj charscript charprop case-table
epa-hook jka-cmpr-hook help abbrev obarray oclosure cl-preloaded button
loaddefs theme-loaddefs faces cus-face macroexp files window
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget keymap hashtable-print-readable backquote threads
w32notify w32 lcms2 multi-tty make-network-process emacs)

Memory information:
((conses 16 97345 9002)
 (symbols 48 7923 0)
 (strings 16 22587 2046)
 (string-bytes 1 609997)
 (vectors 16 12738)
 (vector-slots 8 179418 12186)
 (floats 8 31 52)
 (intervals 40 6159 809)
 (buffers 888 12))