emacs-31 6464453558e: Avoid destructively modifying 'package--builtin-alist'

branch: emacs-31
commit 6464453558e54035360f796a6ee351b5f3e4a461
Author: Philip Kaludercic <[email protected]>
Commit: Philip Kaludercic <[email protected]>

    Avoid destructively modifying 'package--builtin-alist'
    
    * lisp/emacs-lisp/package.el (package--upgradeable-packages):
    Use 'append' instead of 'nconc' to not append the contents of
    'package-alist' to 'package--builtin-alist'.  (Bug#81242)
---
 lisp/emacs-lisp/package.el | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index 12b450d93db..da4642aeb78 100644
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -2186,8 +2186,8 @@ NAME should be a symbol."
                   (package-desc-version (cadr elt))
                   (package-desc-version available)))
              (not (package-vc-p (cadr elt))))))
-    (nconc (and include-builtins (package--builtin-alist))
-           (package--alist)))))
+    (append (and include-builtins (package--builtin-alist))
+            (package--alist)))))
 
 ;;;###autoload
 (defun package-upgrade-all (&optional query)