bug#33870: 27.0.50; xref-goto-xref not configurable

[Juri Linkov]

>>>     Emacs -Q
>>>     C-x 2 ;; split-window-horizontally
>>>     C-x 4 . ;; xref-find-definitions-other-window
>>>     xref-backend-definitions RET
>>>     C-n RET ;; in the resulting *xref* buffer
>>
>> Of course, it doesn't work if you tried it only with part of my changes.
>> When I submitted my initial patch, I tested it in all your test cases,
>> including the above test case that was not broken with my patch.
>>
>> But you asked to break my patch to several pieces and submit them
>> separately to different bug reports.  No wonder that each of them
>> doesn't do what the whole patch did.
>
> We asked to split the patch into "retains old behavior while allowing
> certain customization" and "changes behavior".

The former implies the latter, this is why they were in the same patch.
Please look again at the subject - it says nothing about avoiding
the need to improve old behavior, quite contrary.