diff --git a/dts/Makefile b/dts/Makefile
index 785104e6d6409aa1b956db10107e17ddc6257a6d..922c78c1ca497c18916456359950403ac34774b3 100644
--- a/dts/Makefile
+++ b/dts/Makefile
@@ -36,7 +36,7 @@ $(error Your architecture does not have device tree support enabled. \
 Please define CONFIG_ARCH_DEVICE_TREE))
 
 # We preprocess the device tree file provide a useful define
-DTS_CPPFLAGS := -ansi \
+DTS_CPPFLAGS := -x assembler-with-cpp \
 		-DARCH_CPU_DTS=\"$(SRCTREE)/arch/$(ARCH)/dts/$(CONFIG_ARCH_DEVICE_TREE).dtsi\" \
 		-DBOARD_DTS=\"$(SRCTREE)/board/$(VENDOR)/$(BOARD)/dts/$(DEVICE_TREE).dts\"