diff --git a/libc/kernel/uapi/linux/stddef.h b/libc/kernel/uapi/linux/stddef.h
index 2a5fd95..d5cdf80 100644
--- a/libc/kernel/uapi/linux/stddef.h
+++ b/libc/kernel/uapi/linux/stddef.h
@@ -20,3 +20,5 @@
 #ifndef __always_inline
 #define __always_inline inline
 #endif
+#define __struct_group(TAG,NAME,ATTRS,MEMBERS...) union { struct { MEMBERS } ATTRS; struct TAG { MEMBERS } ATTRS NAME; }
+#define __DECLARE_FLEX_ARRAY(TYPE,NAME) struct { struct { } __empty_ ##NAME; TYPE NAME[]; }