Enable to compile the superbuild alone

CMakeLists.txt

@@ -102,7 +102,11 @@ function (superbuild_find_projects var)
     endif()
   endif()
 
+  if (DEFINED add_project_to_superbuild)
     add_project_to_superbuild(projects)
+  else (DEFINED add_project_to_superbuild)
+	  message(WARNING "The function add_project_to_superbuild is not defined. Only LidarView's common dependencies will be compile.")
+  endif(DEFINED add_project_to_superbuild)
   set("${var}"
     ${projects}
     PARENT_SCOPE)