diff --git a/Makefile b/Makefile
index e0130da..f1ffce0 100644
--- a/Makefile
+++ b/Makefile
@@ -26,6 +26,7 @@ CFLAGS = \
     -I$(FUN_DIR) \
     -I$(SRC_DIR) \
     -I/usr/include/newlib
+    -I$(SRC_DIR)/funconf.h
 
 LD_SCRIPT_IN  = $(FUN_DIR)/ch32fun.ld
 LD_SCRIPT_OUT = $(BUILD)/ch32fun_processed.ld