In Ada 95, the package Ada.Wide_Text_IO.Enumeration_IO is a subpackage
of Wide_Text_IO. In GNAT we make it a child package to avoid loading the
necessary code if Enumeration_IO is not instantiated. See the routine
Rtsfind.Text_IO_Kludge for a description of how we patch up the difference
in semantics so that it is invisible to the Ada programmer.