Issue #1700, reported by Nguyen Quan Son, fix by Fredruk Lundh:
Regular Expression inline flags not handled correctly for some unicode
characters.
diff --git a/Lib/sre_compile.py b/Lib/sre_compile.py
index 7109599..22ab2fd 100644
--- a/Lib/sre_compile.py
+++ b/Lib/sre_compile.py
@@ -525,7 +525,7 @@
         indexgroup[i] = k
 
     return _sre.compile(
-        pattern, flags, code,
+        pattern, flags | p.pattern.flags, code,
         p.pattern.groups-1,
         groupindex, indexgroup
         )