...and fix the call sites that exploited the hack's internals being non-
transparent.

Change-Id: Ib3b06c3945e303d4088c4e1b65be5beed8613bac
Reviewed-on: https://gerrit.libreoffice.org/46325Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>