emacs-29 622838b957: Fix handling of % when searching in .tex or .dtx files

[Arash Esbati]

branch: emacs-29
commit 622838b957e240d700585050e9ddbd036e690513
Author: Arash Esbati <arash@gnu.org>
Commit: Arash Esbati <arash@gnu.org>

    Fix handling of % when searching in .tex or .dtx files
    
    * lisp/textmodes/reftex.el (reftex-compile-variables): Consider %
    when building the regexp for searching only in .dtx files.
    (AUCTeX bug#59638)
---
 lisp/textmodes/reftex.el | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/lisp/textmodes/reftex.el b/lisp/textmodes/reftex.el
index f815419ea4..126b3777f5 100644
--- a/lisp/textmodes/reftex.el
+++ b/lisp/textmodes/reftex.el
@@ -1004,10 +1004,13 @@ This enforces rescanning the buffer on next use."
                   reftex-section-levels))
 
     ;; Calculate the regular expressions
-    (let* (
-;          (wbol "\\(\\`\\|[\n\r]\\)[ \t]*")
-           (wbol "\\(^\\)%?[ \t]*") ; Need to keep the empty group because
-                                    ; match numbers are hard coded
+    (let* (;; (wbol "\\(\\`\\|[\n\r]\\)[ \t]*")
+           ;; Need to keep the empty group because match numbers are
+           ;; hard coded
+           (wbol (concat "\\(^\\)"
+                         (when (string-suffix-p ".dtx" (buffer-file-name) t)
+                           "%")
+                         "[ \t]*"))
            (label-re (concat "\\(?:"
                             (mapconcat #'identity reftex-label-regexps "\\|")
                             "\\)"))