System.RTLVersion constant added

RTL/System.pas

@@ -6,6 +6,13 @@ unit System;
 
 interface
 
+const
+{$IF CompilerVersion < 15}
+  RTLVersion = 14.2006;  // <---,
+{$ELSE}                  //      June, 2020
+  RTLVersion = 15.2006;  // <---'
+{$IFEND}
+
 type
   PPAnsiChar = ^PAnsiChar;