another (stupid?) module question

["C. Ray C." <crayc at tomcramer dot org>]

OK, I see this in boot-9.scm:

(defmacro define-module args
  `(let* ((process-define-module process-define-module)
	  (set-current-module set-current-module)
	  (module (process-define-module ',args)))
     (set-current-module module)
     module))

What is the point of binding process-define-module to
process-define-module and set-current-module to set-current-module?

I think I understand all of the module system except that part... well,
no I don't. modules.c is puzzling as nothing else actually uses anything
from that file.