Causes symbols and their names to be retained.
deliver-keep-symbols &rest symbols
deliver-keep-symbols marks symbols such that they are not shaken out during delivery, and their names are kept.
This is useful for symbols that are not explicitly referenced by Lisp (and hence may be shaken out) but are still needed, for example symbols that are called directly from Java.
deliver-keep-symbols has the same effect as passing :keep-symbols to deliver, but
deliver-keep-symbols is much more convenient because you can use it in your source code before loading the delivery module.
You will typically add a call to
deliver-keep-symbols after the definition(s) of the symbols, as in the example below.
(defun function-called-directly-from-java (x y)
LispWorks Delivery User Guide - 10 Aug 2017