pid1: add option to disable service watchdogs

Add a "systemd.service_watchdogs=" option to the command line which
disables all service runtime watchdogs and emergency actions.

man/systemd.xml

@@ -273,6 +273,15 @@
         to all zeros.</para></listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><option>--service-watchdogs=</option></term>
+
+        <listitem><para>Globally enable/disable all service watchdog timeouts and emergency
+        actions. This setting may also be specified during boot, on the kernel
+        command line via the <varname>systemd.service_watchdogs=</varname>
+        option, see below. Defaults to enabled.</para></listitem>
+      </varlistentry>
+
       <xi:include href="standard-options.xml" xpointer="help" />
       <xi:include href="standard-options.xml" xpointer="version" />
     </variablelist>
@@ -964,6 +973,19 @@
         </para></listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>systemd.service_watchdogs=</varname></term>
+
+        <listitem><para>Takes a boolean argument. If disabled, all service runtime
+        watchdogs (<option>WatchdogSec=</option>) and emergency actions (e.g.
+        <option>OnFailure=</option> or <option>StartLimitAction=</option>) are
+        ignored by the system manager (PID 1); see
+        <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+        Defaults to enabled, i.e. watchdogs and failure actions are processed
+        normally. The hardware watchdog is not affected by this
+        option.</para></listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><varname>systemd.show_status</varname></term>