Please avoid the hacks used to get private Lookup objects in LookupFactory

[sundararajana]

Instead of trying to get Lookup using hacks (sun.misc.Unsafe and deep-reflection on MethodHandles.Lookup), Parboiled API could be adjusted to receive (private) Lookup of Parser class as an API argument.

You do check for a public static method that returns Lookup and then fall back to Unsafe/deep-reflection hack. But, returning private Lookup via public method is a bad idea - basically, opens the class for any caller that can access the parser class! Parboiled API can require Lookup object be passed as an argument from a public API and cache it in LookupFactory.