Bug#3241: derived.el fails in emacs

[Matthew Swift <swift@bu.edu>]

Package: emacs
Version: 19.30-1

Derived.el, after deriving from Text mode or one of its derivatives,
looses.

The problem can be fixed by using the version of derived.el
distributed with emacs-19.31 with the 19.30 binary.  I have not tested
the 19.31 version with 19.30 binary extensively, but it seems to be
fine.

Here is a demonstration of the problem.

Invoke emacs with "emacs -q -no-init-file -l foo.el" where foo.el is
the file below between -----s.  You will be in a newly defined mode
"Bugly".  Press any letter key, and you get an error.  You can't
backtrace this error.

This does not happen when deriving from Fundamental mode.

----------------
; fundamental-mode causes no problem

; text-mode and derivative modes (e.g., latex-mode) cause the problem.

(define-derived-mode bugly-mode text-mode "Bugly"
 "documentation" (message "Firing up Bugly Mode"))

(bugly-mode)
----------------