cmake XRINTERFACE_HAS_OPENVR_SUPPORT examples

Kitware/ParaView Plugins/XRInterface/Plugin/CMakeLists.txt :134 

set_property(
  SOURCE
  pqXRInterfaceDockPanel.cxx
  vtkPVXRInterfaceHelper.cxx
  APPEND PROPERTY
    COMPILE_DEFINITIONS "XRINTERFACE_HAS_OPENVR_SUPPORT=$<BOOL:${openvr_support}>")