In Ada 95, the package Ada.Wide_Text_IO.Decimal_IO is a subpackage of
Wide_Text_IO. In GNAT we make it a child package to avoid loading the
necessary code if Decimal_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.