bug#36447: 27.0.50; New "Unknown keyword" errors

[Eli Zaretskii]

> From: Michael Heerdegen <michael_heerdegen@web.de>
> Date: Sun, 30 Jun 2019 20:23:33 +0200
> 
> I've just rebuilt Emacs from master and am getting "Unknown keyword"
> errors all the time.  Magit broken, Gnus broken, I even got an error
> after typing M-x report-emacs-bug.  This wasn't the case with a build
> from yesterday.
> 
> Here is a backtrace after trying to reinstall Magit:
> 
> Debugger entered--Lisp error: (error "Unknown keyword :link")
>   signal(error ("Unknown keyword :link"))
>   error("Unknown keyword %s" :link)
>   custom-handle-keyword(ido :link (emacs-commentary-link :tag "Commentary" 
> "ido.el") custom-group)

d8aba87a0d5ef84dfedf4c6a73884fa6dc455b24?