diff --git a/libc/include/uchar.h b/libc/include/uchar.h
index 0ec9d2e..a5e72ea 100644
--- a/libc/include/uchar.h
+++ b/libc/include/uchar.h
@@ -34,7 +34,7 @@
 
 __BEGIN_DECLS
 
-#if defined(__GNUC__) && __GNUC__ >= 5 && !defined(__cplusplus)
+#if __STDC_VERSION__ >= 201112L && !defined(__cplusplus)
 typedef __CHAR16_TYPE__ char16_t;
 typedef __CHAR32_TYPE__ char32_t;
 #endif