archivers/urbackup-client: Fix build on 15+
Restore an accidentally deleted patch.
While here update pkg-message.
PR: 289652
Fixes: d70c8a415dd3 (Update 2.5.25.0 => 2.5.26.0)
MFH: 2025Q3
(cherry picked from commit c2bedb478220e73b955f850b040f981a5845199d)