Re: define-derived-mode

[Richard Stallman]

    If I understood correctly, define-generic-mode only started
    constructing automatic defcustoms recently, which was an incompatible
    change.   In that case, it could easily be reversed, which would make
    the two major mode defining functions consistent in this respect.

    For define-minor-mode, the situation is more complex.  It already
    defined defcustoms in 21.3.  So here, removing them would be an
    incompatible change.  It is possible that some users already
    customized these hooks through Custom.

Such a change is no big deal.  Let's turn off generation of these
defcustoms.