[Maxima] How to set file_search_*

[Karl-Dieter Crisman]

Dear list,

How would one set file_search_lisp and friends if (for some reason)
they were empty?  Is there an automated way to do this without
entering them in by hand?  To be more specific, suppose that
FILE_SEARCH_LISP was empty or NIL, and I wanted it to go back to the
default I usually get. (I guess I'm asking if there is a "reset"
command for this.)

Alternately, presumably somewhere in the Maxima startup sequence these
files are generated - in a robust way, even, if the binary is moved,
right?  What command (Lisp or Maxima) is called to do this, if any?

Thank you very much for your help!