diff --git a/libc/kernel/uapi/linux/if.h b/libc/kernel/uapi/linux/if.h
index 12967f7..0821f2b 100644
--- a/libc/kernel/uapi/linux/if.h
+++ b/libc/kernel/uapi/linux/if.h
@@ -134,6 +134,7 @@
     fr_proto __user * fr;
     fr_proto_pvc __user * fr_pvc;
     fr_proto_pvc_info __user * fr_pvc_info;
+    x25_hdlc_proto __user * x25;
     sync_serial_settings __user * sync;
     te1_settings __user * te1;
   } ifs_ifsu;