Fix error in ERC when 'erc-server-coding-system' is customized

* lisp/erc/erc-backend.el (erc-split-line): Handle the case where
'erc-coding-system-for-target' returns a coding-system's symbol.
(Bug#40914)

1 files changed, 2 insertions, 1 deletions

diff --git a/lisp/erc/erc-backend.el b/lisp/erc/erc-backend.el
index 0e3495e139a..526e854beca 100644
--- a/lisp/erc/erc-backend.el
+++ b/lisp/erc/erc-backend.el
@@ -466,7 +466,8 @@ If this is set to nil, never try to reconnect."
 The length is specified in `erc-split-line-length'.
 
 Currently this is called by `erc-send-input'."
-  (let ((charset (car (erc-coding-system-for-target nil))))
+  (let* ((coding (erc-coding-system-for-target nil))
+         (charset (if (consp coding) (car coding) coding)))
     (with-temp-buffer
       (insert longline)
       ;; The line lengths are in octets, not characters (because these