[libnotify] notify-send: Add debug message about server not supporting persistence

[Marco Trevisan <marcotrevi src gnome org>]

commit a674e610ee4f5e4869d29ecd795025ef999f7d8f
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Wed Apr 27 21:32:56 2022 +0200

    notify-send: Add debug message about server not supporting persistence
    
    In case a transient notification is requested but persistence is not
    supported, it's not an error but it is useful to show a debug message
    to clarify that.

 tools/notify-send.c | 6 ++++++
 1 file changed, 6 insertions(+)
---
diff --git a/tools/notify-send.c b/tools/notify-send.c
index a72dc94..926cd11 100644
--- a/tools/notify-send.c
+++ b/tools/notify-send.c
@@ -325,6 +325,12 @@ main (int argc, char *argv[])
         if (transient) {
                 notify_notification_set_hint (notify, "transient",
                                               g_variant_new_boolean (TRUE));
+
+                if (!server_has_capability ("persistence")) {
+                        g_debug ("Persistence is not supported by the "
+                                 "notifications server. "
+                                 "All notifications are transient.");
+                }
         }
 
         g_free (body);