bug#69100: ecb 2.50 doesn't work with emacs 29.2

[Eli Zaretskii]

> Date: Tue, 13 Feb 2024 10:14:43 +0000
> From:  "Vaysenberg, Igor" via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> when I run ecb-activate the following error occured:
> ECB 2.50 uses CEDET 2.0 (contains semantic 2.2, eieio 1.4, speedbar 1.0).
> helm-M-x-execute-command: Symbol’s function definition is void: 
> eieio--defgeneric-init-formUnable to load
> color "headerColor"
> 
> The previous emacs version 28.x doesn't have this issue.
> Please advise how to fix.

Please show the full Lisp backtrace (set debug-on-error to a non-nil
value if needed).  It is almost impossible to guess what went wrong
without seeing at least that much.

Alternatively, post a recipe, starting from "emacs -Q" (and loading
any optional packages) needed to reproduce the error, so that someone
could try reproducing it on their machine.

Thanks.