Allow elogind to exit when dbus is closed

As reported in ticket #16177 by Joe Locash, switching from runlevel
3 to 1 and back would render elogind useless: it is still running
but not connected to the bus, because dbus is killed in runlevel 1
and then restarted in runlevel 3. The added "sed" allows elogind to
exit when dbus is killed. This is the normal behavior of daemons
using dbus.

general/sysutils/elogind.xml

@@ -154,6 +154,12 @@ File systems --->
 
 <screen><userinput>sed -i '/Disable polkit/,+8 d' meson.build &amp;&amp;
 
+sed '/request_name/i\
+r = sd_bus_set_exit_on_disconnect(m->bus, true);\
+if (r &lt; 0)\
+    return log_error_errno(r, "Failed to set exit on disconnect: %m");' \
+    -i src/login/logind.c &amp;&amp;
+
 mkdir build &amp;&amp;
 cd    build &amp;&amp;
 
@@ -191,6 +197,12 @@ ln -sfvn elogind /usr/include/systemd</userinput></screen>
       installed.
     </para>
 
+    <para>
+      <command>sed ... src/login/logind.c</command>: This change allows the
+      elogind daemon to exit when it is disconnected from dbus (for example
+      when dbus is killed).
+    </para>
+
     <para>
       <parameter>-Dcgroup-controller=elogind</parameter>: This switch ensures
       that <application>elogind</application> is selected as the cgroup

introduction/welcome/changelog.xml

@@ -41,6 +41,16 @@
       </itemizedlist>
     </listitem>
     -->
+    <listitem revision="sysv">
+      <para>March 12th, 2022</para>
+      <itemizedlist>
+        <listitem>
+          <para>[pierre] - Allow elogind to exit when dbus is closed. Fixes
+          <ulink url="&blfs-ticket-root;16177">#16177</ulink>.</para>
+        </listitem>
+      </itemizedlist>
+    </listitem>
+
     <listitem>
       <para>March 11th, 2022</para>
       <itemizedlist>