diff --git a/libc/kernel/uapi/asm-generic/mman.h b/libc/kernel/uapi/asm-generic/mman.h
index 5a0242a..5db0e52 100644
--- a/libc/kernel/uapi/asm-generic/mman.h
+++ b/libc/kernel/uapi/asm-generic/mman.h
@@ -33,4 +33,6 @@
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define MCL_CURRENT 1
 #define MCL_FUTURE 2
+#define MCL_ONFAULT 4
 #endif
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */