CL is cryptic

I'm trying to define export-defun macro, that would automatically export defined function, but produces error "These symbols are not accessible in the XYZ package" with ASDF. How would you fix it?


(defmacro export-defun (pkg name args &body body)
  (unless (find-package pkg)
    (make-package pkg))
  (let ((sym (intern (symbol-name name) pkg)))
    `(progn (defun ,sym ,args ,@body)
            (export ',sym))))

How would you fix it?
Use C89.