LibreOffice code, when used in a program through LibreOfficeKit, needs to be
aware of that in certain crucial spots, to avoid behaviour and functionality
that makes no sense in a LibreOfficeKit scenario. As LibreOfficeKit uses a
normal LibreOffice installation to perform its job, this can't be a
compile-time choice. Also, none of the existing run-time "headlessness" modes
fully match what is needed.

Change-Id: Iaccf7f958c549f019b508854800519f54dcadb11