This makes --disable-gui option build successfully again - which
means we again run on a headless server w/o any X11 or OpenGL libs.

Change-Id: I60019af571aecdac277adbe6d34d5fff065014f9
Reviewed-on: https://gerrit.libreoffice.org/50214Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Tested-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>