sal_Int32 appears to be the widest type we need here

Change-Id: I1859936dbe7b6a95840c638c8ca5d4148849e12d
Reviewed-on: https://gerrit.libreoffice.org/42154Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>