diff --git a/ch32v003fun/ch32v003fun.mk b/ch32v003fun/ch32v003fun.mk
index ab273c366f2ee6c061aecbe87f81059f4bfef81a..15330b3b62a6a343138612e7198d59cf3a89f9ca 100644
--- a/ch32v003fun/ch32v003fun.mk
+++ b/ch32v003fun/ch32v003fun.mk
@@ -13,7 +13,7 @@ CFLAGS+= \
 	-I$(CH32V003FUN)/../extralibs \
 	-I$(CH32V003FUN) \
 	-nostdlib \
-	-I. -Wall
+	-I. -Wall $(EXTRA_CFLAGS)
 
 LINKER_SCRIPT?=$(CH32V003FUN)/ch32v003fun.ld