Which means xmlsecurity can be again a module that has no public
headers.

Change-Id: I3d0b03680398f80196fac187263e770fd44ed0ed
Reviewed-on: https://gerrit.libreoffice.org/41966Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>