grep.el bug?

[David Abrahams <dave@boost-consulting.com>]

I just rebuilt emacs from CVS.  On line 541 of grep.el, a change was
made about a year ago that seems to be breaking grep-find for me.

    (let ((null-device nil))		; see grep
      (grep command-args))))

This always leads to the following backtrace for me:

Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  call-process("find" nil nil nil nil "-print0")
  grep-compute-defaults()
  grep-process-setup()
  compilation-start("find . -type f -not -path \"*/CVS/*\" ...)
  grep("find . -type f -not -path \"*/CVS/*\" -not -name \ ...)
  grep-find("find . -type f -not -path \"*/CVS/*\" -not    ...)
  call-interactively(grep-find)
  execute-extended-command(nil)
  call-interactively(execute-extended-command)

As far as I can tell, null-device gets passed as the 5th argument to
call-process, which expects only strings after its 4th argument.  But
this can't have remained broken for everyone for a whole year, can it?
So I must be missing something.  The comment that directs me to "see
grep" leaves me completely in the dark.

Clues, anyone?

Thanks in advance,
-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com