Index: sys/fs/tmpfs/tmpfs_vnops.c
===================================================================
--- sys/fs/tmpfs/tmpfs_vnops.c
+++ sys/fs/tmpfs/tmpfs_vnops.c
@@ -1381,6 +1381,11 @@
 		*retval = 64;
 		break;
 
+	case _PC_ACL_EXTENDED:
+	case _PC_ACL_NFS4:
+		*retval = 0;		/* not supported */
+		break;
+
 	default:
 		error = vop_stdpathconf(v);
 	}