+# LC_HAVE_POSIX_ACL_VALID_USER_NS
+#
+# 4.8 posix_acl_valid takes struct user_namespace
+#
+AC_DEFUN([LC_HAVE_POSIX_ACL_VALID_USER_NS], [
+LB_CHECK_COMPILE([if 'posix_acl_valid' takes 'struct user_namespace'],
+posix_acl_valid, [
+ #include <linux/fs.h>
+ #include <linux/posix_acl.h>
+],[
+ posix_acl_valid((struct user_namespace*)NULL, (const struct posix_acl*)NULL);
+],[
+ AC_DEFINE(HAVE_POSIX_ACL_VALID_USER_NS, 1,
+ [posix_acl_valid takes struct user_namespace])
+])
+]) # LC_HAVE_POSIX_ACL_VALID_USER_NS
+
+#