Adapt to `derived-mode-p` changes in emacs-master

[thisch]

Adapt to `derived-mode-p` changes in emacs-master

[tarsius]

The problem is that we also have to support released versions of Emacs and those don't support a list as the first/only argument. I've silenced this warning in a few places, while I am waiting for this deprecation to be reverted. It seems to be taking longer than expected though, given that hundreds of packages must be affected. You could help by reporting this issue on debbugs.

[tarsius]

I've informed Stefan and he is looking into it. (I tried responding to https://debbugs.gnu.org/cgi/bugreport.cgi?bug=67034, but apparently I only send a private message to him.)

[tarsius]

For now we don't get these warnings anymore.

(defun derived-mode-p (&optional modes &rest old-modes)
 "Non-nil if the current major mode is derived from one of MODES.
MODES should be a list of symbols or a single mode symbol instead of a list.
We also still support the deprecated calling convention:
\(derived-mode-p &rest MODES)."
 (declare (side-effect-free t)
          ;; FIXME: It's cumbersome for external packages to write code which
          ;; accommodates both the old and the new calling conventions *and*
          ;; doesn't cause spurious warnings.  So let's be more lenient
          ;; for now and maybe remove `deprecated-args' for Emacs-31.
          (advertised-calling-convention (modes &rest deprecated-args) "30.1"))
 (provided-mode-derived-p major-mode (if old-modes (cons modes old-modes)
                                       modes)))