(if (eq (delivery-value :console) t) nil :default)
Windows only: The name of a file containing the icon to use, in Windows
(meaning no icon -- not recommended except for console applications) or
(which uses the icon from the LispWorks image).
to achieve the same effect on Mac OS X, do not pass
but put your delivered image in a suitable application bundle which contains the application icon. See the examples in the LispWorks library directory
LispWorks Delivery User Guide - 13 Dec 2011