log.go
func init() {
	for _, f := range strings.Split(os.Getenv("LOGFLAGS"), ",") {
		switch f {
		case "longfile":
			defaultFlags |= Llongfile
		case "shortfile":
			defaultFlags |= Lshortfile
		}
	}
}
func init() {
	for _, f := range strings.Split(os.Getenv("LOGFLAGS"), ",") {
		switch f {
		case "longfile":
			defaultFlags |= Llongfile
		case "shortfile":
			defaultFlags |= Lshortfile
		}
	}
}
// Read logger flags from the LOGFLAGS environment variable.  Multiple flags can
// be set at once, separated by commas.