(rmail-header-summary): Ignore letter-case of month names. (Bug#3987)

1 files changed, 7 insertions, 4 deletions

diff --git a/lisp/mail/rmailsum.el b/lisp/mail/rmailsum.el
index c35e4856f9c..b8175c36f23 100644
--- a/lisp/mail/rmailsum.el
+++ b/lisp/mail/rmailsum.el
@@ -518,16 +518,19 @@ the message being processed."
    (concat (save-excursion
              (if (not (re-search-forward "^Date:" nil t))
                  "      "
-               (cond ((re-search-forward "\\([^0-9:]\\)\\([0-3]?[0-9]\\)\\([- \t_]+\\)\\([adfjmnos][aceopu][bcglnprtvy]\\)"
-                       (line-end-position) t)
+               ;; Match month names case-insensitively
+               (cond ((let ((case-fold-search t))
+                        (re-search-forward "\\([^0-9:]\\)\\([0-3]?[0-9]\\)\\([- \t_]+\\)\\([adfjmnos][aceopu][bcglnprtvy]\\)"
+                                           (line-end-position) t))
                       (format "%2d-%3s"
                               (string-to-number (buffer-substring
                                                  (match-beginning 2)
                                                  (match-end 2)))
                               (buffer-substring
                                (match-beginning 4) (match-end 4))))
-                     ((re-search-forward "\\([^a-z]\\)\\([adfjmnos][acepou][bcglnprtvy]\\)\\([-a-z \t_]*\\)\\([0-9][0-9]?\\)"
-                       (line-end-position) t)
+                     ((let ((case-fold-search t))
+                        (re-search-forward "\\([^a-z]\\)\\([adfjmnos][acepou][bcglnprtvy]\\)\\([-a-z \t_]*\\)\\([0-9][0-9]?\\)"
+                                           (line-end-position) t))
                       (format "%2d-%3s"
                               (string-to-number (buffer-substring
                                                  (match-beginning 4)