message: Guard install of (optional) libs
  More robust fix for
diff: -## Copyright 2009-2019 Intel Corporation
  +## Copyright 2009-2020 Intel Corporation
  ## SPDX-License-Identifier: Apache-2.0
  macro(ospray_install_namelink NAME TARGET_NAME)
  @@ -65,10 +65,14 @@ if (OSPCOMMON_TASKING_TBB)
  endif()
  macro(ospray_add_dependent_lib TARGET_NAME)
  + if (TARGET ${TARGET_NAME})
  get_target_property(CONFIGURATIONS ${TARGET_NAME} IMPORTED_CONFIGURATIONS)
  list(GET CONFIGURATIONS 0 CONFIGURATION)
  get_target_property(LIBRARY ${TARGET_NAME} IMPORTED_LOCATION_${CONFIGURATION})
  list(APPEND DEPENDENT_LIBS ${LIBRARY})
  + else()
  + message(STATUS "Skipping target '${TARGET_NAME}")
  + endif()
  endmacro()
  ospray_add_dependent_lib(ospcommon::ospcommon)
  @@ -95,6 +99,7 @@ if (WIN32)
  install(PROGRAMS ${DEPENDENT_LIBS}
  DESTINATION ${CMAKE_INSTALL_BINDIR} COMPONENT redist)
  else()
  + # TODO use ospray_add_dependent_lib(embree) when v3.10 (with targets) is minimum
  list(APPEND DEPENDENT_LIBS ${EMBREE_LIBRARY})
  install(PROGRAMS ${DEPENDENT_LIBS}
  DESTINATION ${CMAKE_INSTALL_LIBDIR} COMPONENT redist)
  