Most of ubsan.patch seems to have been applied upstream, and I can’t
reproduce the issue referenced for the remaining bits, anyway it is
better to push such changes upstream first.

Change-Id: Ie56786c01c06d3542052cd91e36d1f707092beba
Reviewed-on: https://gerrit.libreoffice.org/15643Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>