assq-delete-all patch

[Lars Hansen <larsh@math.ku.dk>]

The built-in function assq ignores elements of the list that are not conses.
But the function assq-delete-all in subr.el fails. IMHO that is 
inconsequent.
Therefore I suggest this patch:

  (defun assq-delete-all (key alist)
    "Delete from ALIST all elements whose car is KEY.
! Return the modified alist."
    (let ((tail alist))
      (while tail
!       (if (eq (car (car tail)) key)
        (setq alist (delq (car tail) alist)))
        (setq tail (cdr tail)))
      alist))
--- 2048,2058 ----
 
  (defun assq-delete-all (key alist)
    "Delete from ALIST all elements whose car is KEY.
! Return the modified alist.
! Elements of ALIST that are not conses are ignored."
    (let ((tail alist))
      (while tail
!       (if (and (consp (car tail)) (eq (car (car tail)) key))
        (setq alist (delq (car tail) alist)))
        (setq tail (cdr tail)))
      alist))