diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 0f207b3..f2d69d5 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -2,9 +2,7 @@
 # Makefile for RTC class/drivers.
 #
 
-ifeq ($(CONFIG_RTC_DEBUG),y)
-	EXTRA_CFLAGS		+= -DDEBUG
-endif
+ccflags-$(CONFIG_RTC_DEBUG)	:= -DDEBUG
 
 obj-$(CONFIG_RTC_LIB)		+= rtc-lib.o
 obj-$(CONFIG_RTC_HCTOSYS)	+= hctosys.o