Escape NUL bytes in X selections (Bug#6991)

* lisp/term/w32-win.el (w32--set-selection):
* lisp/select.el (xselect--encode-string): Replace NUL bytes with
"\0".
* doc/emacs/killing.texi: Document new behavior.
* etc/NEWS (times): Announce it.

1 files changed, 3 insertions, 0 deletions

diff --git a/lisp/select.el b/lisp/select.el
index 4849d7d515e..579c5c7e2ee 100644
--- a/lisp/select.el
+++ b/lisp/select.el
@@ -475,6 +475,9 @@ two markers or an overlay.  Otherwise, it is nil."
            (t
             (error "Unknown selection type: %S" type)))))
 
+      ;; Most programs are unable to handle NUL bytes in strings.
+      (setq str (replace-regexp-in-string "\0" "\\0" str t t))
+
       (setq next-selection-coding-system nil)
       (cons type str))))