Try to solve compilation failure for msdos OS

packages/rtl-objpas/src/inc/rtti.pp

@@ -7453,7 +7453,7 @@ begin
       ptField:
         {$ifdef cpu8086}
         { convert to the correct pointer type }
-        AValue.Cast(FPropInfo^.PropType).ExtractRawData(PPointer(@(Pointer(Instance)+FPropInfo^.SetProc))^);
+        AValue.Cast(FPropInfo^.PropType).ExtractRawData(Pointer(Instance)+CodePtrUInt(FPropInfo^.SetProc));
         {$else}
         AValue.Cast(FPropInfo^.PropType).ExtractRawData(Pointer(Instance)+PtrUInt(FPropInfo^.SetProc));
         {$endif}
@@ -8467,4 +8467,4 @@ initialization
 {$ifdef SYSTEM_HAS_INVOKE}
   InitSystemFunctionCallManager;
 {$endif}
-end.
+end.