#4873 Give add_acknowledger SCM &, not Protected_scm &

[David Kastrup]

Give add_acknowledger SCM &, not Protected_scm &

This one annoyed me, this looks cleaner.

Also contains commit:

operator SCM & () for Protected_scm

This allows passing SCM reference parameters that are
actually based on Protected_scm.

http://codereview.appspot.com/296310043

[Anonymous]

Passes make, make check and a full make doc.

[Anonymous]

Patch on countdown for June 9th.

[David Kastrup]

Pushed to staging as
commit 014fe25e13112b1e215e2fec5d1a466f6a8ac255
Author: David Kastrup dak@gnu.org
Date: Wed Jun 1 20:57:26 2016 +0200

Issue 4873/2: Give add_acknowledger SCM &, not Protected_scm &

commit 91723da7360b372904979b2d572f3f941ebbc924
Author: David Kastrup dak@gnu.org
Date: Wed Jun 1 19:38:35 2016 +0200

Issue 4873/1: operator SCM & () for Protected_scm

This allows passing SCM reference parameters that are
actually based on Protected_scm.