--- Linux-Clone/Clone.xs	2017/11/07 18:15:29	1.4
+++ Linux-Clone/Clone.xs	2022/07/25 10:59:29	1.5
@@ -144,6 +144,9 @@
 #   ifdef CLONE_NEWCGROUP
       const_iv_clone (NEWCGROUP)
 #   endif
+#   ifdef CLONE_PIDFD
+      const_iv_clone (PIDFD)
+#   endif
 #   ifdef SYS_kcmp
       const_iv (KCMP_FILE)
       const_iv (KCMP_VM)