all: define Berlin hard fork spec

cmd/utils/flags.go

@@ -230,6 +230,10 @@ var (
 		Usage: "Megabytes of memory allocated to bloom-filter for pruning",
 		Value: 2048,
 	}
+	OverrideBerlinFlag = cli.Uint64Flag{
+		Name:  "override.berlin",
+		Usage: "Manually specify Berlin fork-block, overriding the bundled setting",
+	}
 	// Light server and client settings
 	LightServeFlag = cli.IntFlag{
 		Name:  "light.serve",