return []string{"LD_LIBRARY_PATH"}
	case "hpux":
		return []string{"LD_LIBRARY_PATH", "SHLIB_PATH"}
	case "irix":
		return []string{"LD_LIBRARY_PATH", "LD_LIBRARYN32_PATH", "LD_LIBRARY64_PATH"}
	case "illumos", "solaris":
		return []string{"LD_LIBRARY_PATH", "LD_LIBRARY_PATH_32", "LD_LIBRARY_PATH_64"}
	case "windows":
		return []string{"SystemRoot", "COMSPEC", "PATHEXT", "WINDIR"}
	}
	return nil
}()