Don’t attempt to modify constant conses

From a patch privately suggested by Mattias Engdegård on 2020-05-11
in a followup to Bug#40671.
* admin/charsets/cp51932.awk:
* admin/charsets/eucjp-ms.awk:
Generate code that does not modify constant conses.
* doc/misc/emacs-mime.texi (Encoding Customization):
* lisp/emacs-lisp/byte-opt.el (byte-compile-side-effect-free-ops):
* lisp/frameset.el (frameset-persistent-filter-alist):
* lisp/gnus/gnus-sum.el (gnus-article-mode-line-format-alist):
Use append instead of nconc.
* lisp/language/japanese.el (japanese-ucs-cp932-to-jis-map)
(jisx0213-to-unicode):
Use mapcar instead of mapc.
* lisp/language/lao-util.el (lao-transcription-consonant-alist)
(lao-transcription-vowel-alist):
* lisp/language/tibetan.el (tibetan-subjoined-transcription-alist):
Use copy-sequence.
* test/src/fns-tests.el (fns-tests-nreverse):
(fns-tests-sort, fns-tests-collate-sort)
(fns-tests-string-version-lessp, fns-tests-mapcan):
Use copy-sequence, vector, and list.

1 files changed, 3 insertions, 3 deletions

diff --git a/lisp/gnus/gnus-sum.el b/lisp/gnus/gnus-sum.el
index 6f367692ddd..341f04ad772 100644
--- a/lisp/gnus/gnus-sum.el
+++ b/lisp/gnus/gnus-sum.el
@@ -1501,9 +1501,9 @@ the type of the variable (string, integer, character, etc).")
 
 ;; This is here rather than in gnus-art for compilation reasons.
 (defvar gnus-article-mode-line-format-alist
-  (nconc '((?w (gnus-article-wash-status) ?s)
-           (?m (gnus-article-mime-part-status) ?s))
-         gnus-summary-mode-line-format-alist))
+  (append '((?w (gnus-article-wash-status) ?s)
+            (?m (gnus-article-mime-part-status) ?s))
+          gnus-summary-mode-line-format-alist))
 
 (defvar gnus-last-search-regexp nil
   "Default regexp for article search command.")