bug#20353: M-. sometimes jumps in another window

[Stefan Monnier]

> Are there some particular settings that make the xref buffer appear in a new
> frame?
Yes, I have some display-buffer-alist settings for that.
I just reproduced the problem with:

  src/emacs -Q --eval '(setq special-display-regexps (list "^\\*"))'
  C-x C-f src/emacs.c
  C-x 5 2
  C-s pthread_sigmask
  M-. RET
  <click on one of the entries>

It seems always the same of the 2 frames is used for the jump, so
depending on which one is used for the M-. the behavior is either the
expected one or not.


        Stefan