updated for version 7.3.1217
Problem:    New regexp engine: Can't handle \%[[ao]]. (Yukihiro Nakadaira)
Solution:   Support nested atoms inside \%[].
diff --git a/src/testdir/test64.ok b/src/testdir/test64.ok
index fda5892..7021d18 100644
--- a/src/testdir/test64.ok
+++ b/src/testdir/test64.ok
@@ -836,6 +836,9 @@
 OK 0 - \%[bar]x
 OK 1 - \%[bar]x
 OK 2 - \%[bar]x
+OK 0 - b\%[[ao]r]
+OK 1 - b\%[[ao]r]
+OK 2 - b\%[[ao]r]
 OK 0 - goo\|go
 OK 1 - goo\|go
 OK 2 - goo\|go