diff --git a/sys/include/string_utils.h b/sys/include/string_utils.h
index 50f3db8a47..46bfb3def4 100644
--- a/sys/include/string_utils.h
+++ b/sys/include/string_utils.h
@@ -47,7 +47,7 @@ extern "C" {
  *
  * for all other cases, we provide it here
  */
-#if !defined(BOARD_NATIVE) \
+#if !defined(CPU_NATIVE) \
     && !(IS_USED(MODULE_PICOLIBC) && __BSD_VISIBLE) \
     && !(IS_USED(MODULE_NEWLIB) && __BSD_VISIBLE && !defined(MCU_ESP8266))