code: func GetSystemAttributePaths(mp *gitattr.MacroProcessor, env Env) []AttributePath {
  	prefix, _ := env.Get("PREFIX")
  	if len(prefix) == 0 {
  		prefix = string(filepath.Separator)
  	}
  
  	path := filepath.Join(prefix, "etc", "gitattributes")
  
  	if _, err := os.Stat(path); os.IsNotExist(err) {
  		return nil
  	}
  
  	return attrPaths(mp, path, "", true)
  }
docs: // GetSystemAttributePaths behaves as GetAttributePaths, and loads information
  // only from the system gitattributes file, respecting the $PREFIX environment
  // variable.