support tar verbosity

Config.in

@@ -62,6 +62,9 @@ config BR2_WGET
 	string
 	default "wget --passive-ftp"
 
+config BR2_TAR_VERBOSITY
+	string
+	default "no"
 
 source "toolchain/Config.in"
 

Makefile

@@ -35,6 +35,12 @@ ifeq ($(filter $(noconfig_targets),$(MAKECMDGOALS)),)
 -include $(TOPDIR).config
 endif
 
+ifeq ($(strip $(BR2_TAR_VERBOSITY)),"yes")
+TAR_VERBOSITY=v
+else
+TAR_VERBOSITY=
+endif
+
 ifeq ($(strip $(BR2_HAVE_DOT_CONFIG)),y)
 
 #############################################################