...similar to dc06c8f4 "-Werror=redundant-move
(GCC 9), take two"

Change-Id: I53c181887e254aa3d924c134c77d7d0230717d5c
Reviewed-on: https://gerrit.libreoffice.org/59750
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>