message: Always include GNUInstallDirs
diff: @@ -181,6 +181,7 @@ MACRO(OSPRAY_ADD_LIBRARY name type)
  ENDMACRO()
  ## Target install macros for OSPRay libraries ##
  +INCLUDE(GNUInstallDirs)
  MACRO(OSPRAY_INSTALL_LIBRARY name component)
  INSTALL(TARGETS ${name}
  