[gtkada] AI95-00299 Accessibility rules and generics

[Dan Eilers]

One of the source files from gtkada appears to demonstrate the
compatibility problem created by AI95-00299.

GtkAda-1.2.12/src/gtk-marshallers.adb, line 79:
    return (Func  => To_General_Handler (Cb), Proxy => Call'Access);

where Call'Access is of type Handler_Proxy, which is declared
outside the current generic unit (in an enclosing generic unit).

        -- Dan Eilers