emacs-29 6b60c8142ea: Fix systemd unit completion for old versions of systemd

[Eli Zaretskii]

branch: emacs-29
commit 6b60c8142ea10b774cd01db39f803f806df5fc5b
Author: Liu Hui <liuhui1610@gmail.com>
Commit: Eli Zaretskii <eliz@gnu.org>

    Fix systemd unit completion for old versions of systemd
    
    * lisp/pcmpl-linux.el (pcmpl-linux--systemd-units): Use '--no-legend'
    for compatibility with older versions of systemctl.  (Bug#63411)
---
 lisp/pcmpl-linux.el | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lisp/pcmpl-linux.el b/lisp/pcmpl-linux.el
index 082072d87d2..589b4799c8d 100644
--- a/lisp/pcmpl-linux.el
+++ b/lisp/pcmpl-linux.el
@@ -119,7 +119,8 @@ Test is done using `equal'."
   (with-temp-buffer
     (apply #'call-process
            "systemctl" nil '(t nil) nil
-           "list-units" "--full" "--legend=no" "--plain" args)
+           ;; "--legend=no" doesn't exist before systemd v248
+           "list-units" "--full" "--no-legend" "--plain" args)
     (goto-char (point-min))
     (let (result)
       (while (re-search-forward (rx bol (group (+ (not space)))