Use an environment variable to activate debug mode, instead of a package-specific flag

docker/docker.go

@@ -21,7 +21,9 @@ func main() {
 	flDaemon := flag.Bool("d", false, "Daemon mode")
 	flDebug := flag.Bool("D", false, "Debug mode")
 	flag.Parse()
-	rcli.DEBUG_FLAG = *flDebug
+	if *flDebug {
+		os.Setenv("DEBUG", "1")
+	}
 	if *flDaemon {
 		if flag.NArg() != 0 {
 			flag.Usage()

utils.go

@@ -45,7 +45,7 @@ func Download(url string, stderr io.Writer) (*http.Response, error) {
 // Debug function, if the debug flag is set, then display. Do nothing otherwise
 // If Docker is in damon mode, also send the debug info on the socket
 func Debugf(format string, a ...interface{}) {
-	if rcli.DEBUG_FLAG {
+	if os.Getenv("DEBUG") != "" {
 
 		// Retrieve the stack infos
 		_, file, line, ok := runtime.Caller(1)