o "unique" class (and interface) type aliases should actually not exist at
     all except for overload resolution. All the rest (VMT, UUID, RTTI, ...)
     should be taken from the aliased class/interface
   o there is one Delphi-incompatibily left after this change, but it shouldn't
     matter: tw8180 does not compile if you change the declaration to
     "tcl=class(TInterfacedObject,XStr,iinterface)", while Kylix does compile
     that. It doesn't really matter though, because in Kylix this actually
     adds iinterface twice as implemented interface, so there is no point
     in accepting this.

git-svn-id: trunk@46773 -