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, 4 insertions, 0 deletions

diff --git a/doc/emacs/killing.texi b/doc/emacs/killing.texi
index 47de0531292..0b5efd04a18 100644
--- a/doc/emacs/killing.texi
+++ b/doc/emacs/killing.texi
@@ -519,6 +519,10 @@ when exiting Emacs; if you wish to prevent Emacs from transferring
 data to the clipboard manager, change the variable
 @code{x-select-enable-clipboard-manager} to @code{nil}.
 
+  Since strings containing NUL bytes are usually truncated when passed
+through the clipboard, Emacs replaces such characters with ``\0''
+before transfering them to the system's clipboard.
+
 @vindex select-enable-primary
 @findex clipboard-kill-region
 @findex clipboard-kill-ring-save