UITypes: fix SizeOf() of sets for LCL compatibility

(cherry picked from commit 72fd08df038e0fc004614d75ff49d83466d154b0)

packages/rtl-objpas/src/inc/system.uitypes.pp

@@ -16,6 +16,9 @@
 unit System.UITypes;
 {$mode delphi}
 
+// LCL defined all sets with SizeOf()=4
+{$PACKSET FIXED}
+
 interface
 
 Type