make values unique across modules.
check if flag used in correct module.

Change-Id: I656ffd3d527dd895777e14e1cc933c8b9b3f6e46
Reviewed-on: https://gerrit.libreoffice.org/28906Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Noel Grandin <noel.grandin@collabora.co.uk>