code: def add_targets_to_INSTALLED_FILES(target, source, env):
      
      global _INSTALLED_FILES, _UNIQUE_INSTALLED_FILES
      _INSTALLED_FILES.extend(target)
  
      _UNIQUE_INSTALLED_FILES = None
      return (target, source)
docs: An emitter that adds all target files to the list stored in the
      _INSTALLED_FILES global variable. This way all installed files of one
      scons call will be collected.