Re: master 70341cab3e: string-equal-ignore-case: new function

[Lars Ingebrigtsen <larsi@gnus.org>]

Sam Steingold <sds@gnu.org> writes:

> -;; case-insensitive case, but it has to cope with null args.
> -;; (`string-equal' uses symbol print names.)
> -(defun gnus-string-equal (x y)
> -  "Like `string-equal', except it compares case-insensitively."
> -  (and (= (length x) (length y))
> -       (or (string-equal x y)
> -	   (string-equal (downcase x) (downcase y)))))

We don't remove non-internal functions like this (because they may be
used by third parties).  Instead make it obsolete.

> -	      (when (gnus-string-equal
> +	      (when (string-equal-ignore-case
>  		     (message-fetch-field "followup-to")
>  		     (message-fetch-field "newsgroups"))

And the arguments here may be nil, which will signal an error.