bug#36879: 26.2; OSC 52 paste in term/xterm.el not working

[Stefan Monnier]

> The question is rather, how did this code ever work in the first
> place?

Here's what I remember from it:
- I did test the code with the xterm that comes with Debian.
  I definitely remember making it work it in one direction (paste or
  yank, can't remember), not sure if I did get it to work in both
  directions at the time.
- The feature is fundamentally dodgy from a security perspective.
- This is the first case I hear of someone actually using that feature
  (or trying to) since it was added to Emacs.

So I'm not sure it's worth the trouble supporting this, really:
In many/most cases `xclip-mode` can be used instead, and is much
more straightforward.


        Stefan