And backport a post-release fix that fixes the Windows build.

EPUBExportFilter in writerperfect will want to use this.

Change-Id: I020cd2abfd0daa731f4079320b18a6d857874278
Reviewed-on: https://gerrit.libreoffice.org/40679Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>