bug#39345: 28.0.50; rcirc-authenticate-before-join due to case sensitive mismatch

[Jake Nelson <jake.nelson@gmail.com>]

1. join irc.freenode.net with a lowercase nick "examplenick"
2. authenticate to nickserv
3. nickserv echos back  "-NickServ- You are now identified for
"Examplenick" capitalizing the nickname.
4. rcirc-authenticate-before-join does not trigger, so no channels are
auto-joined.

The existing check is case sensitive.  The patch below fixes the issue
for me on freenode.

diff --git a/lisp/net/rcirc.el b/lisp/net/rcirc.el
index 5722582ab6..b516c8d0a6 100644
--- a/lisp/net/rcirc.el
+++ b/lisp/net/rcirc.el
@@ -2624,12 +2624,12 @@ rcirc-check-auth-status
         (when (or
                (and ;; nickserv
                 (string= sender "NickServ")
-                (string= target rcirc-nick)
-                (member message
+                (string= (downcase target) (downcase rcirc-nick))
+                (member (downcase message)
                         (list
-                         (format "You are now identified for
\C-b%s\C-b." rcirc-nick)
-                        (format "You are successfully identified as
\C-b%s\C-b." rcirc-nick)
-                         "Password accepted - you are now recognized."
+                         (downcase (format "You are now identified
for \C-b%s\C-b." rcirc-nick))
+                        (downcase (format "You are successfully
identified as \C-b%s\C-b." rcirc-nick))
+                         (downcase "Password accepted - you are now
recognized.")
                          )))
                (and ;; quakenet
                 (string= sender "Q")