#ifdef out generation of \U escapes unless Py_UNICODE_WIDE. This

#caused warnings with the VMS C compiler.  (SF bug #442998, in part.)
On a narrow system the current code should never be executed since ch
will always be < 0x10000.

Marc-Andre: you may end up fixing this a different way, since I
believe you have plans to generate \U for surrogate pairs.  I'll leave
that to you.