diff --git a/platformio.ini b/platformio.ini
index 7ab6a396ed2f437fc242993fcbcd52a33c93b782..b1626df25cd0b6ed47b99b90832676c03463dcd3 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -15,7 +15,7 @@ extends = fun_base
 ; for examples that use ch32v003fun as their base
 [fun_base]
 board_build.ldscript = ch32v003fun/ch32v003fun.ld
-build_flags = -flto -Ich32v003fun -I/usr/include/newlib -DTINYVECTOR -lgcc
+build_flags = -flto -Ich32v003fun -I/usr/include/newlib -DTINYVECTOR -lgcc -Iextralibs
 build_src_filter = +<ch32v003fun>
 
 [env:blink]