and ofz+ubsan warning

Change-Id: I55db222dc73432171d9d0b8b8e41371963ccb955
Reviewed-on: https://gerrit.libreoffice.org/43412Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>