Following code causes error "Operator is not overloaded: "TObject" < 
"TObject""
How to make it work?
program generictest2;
{$mode objfpc}{$H+}
uses
   fgl;
operator < (a: TObject; b: TObject): boolean;
begin
   result := PtrInt(a) < PtrInt(b);
end;
type
   TMyMap = specialize TFPGMap <TObject, TObject>;
begin
end.