make-directive-index: link to systemd options

Makefile.am

@@ -699,6 +699,7 @@ EXTRA_DIST += \
 	man/index.html
 
 XML_DIRECTIVE_FILES = \
+	man/systemd.xml \
 	man/systemd.unit.xml \
 	man/systemd.service.xml \
 	man/systemd.socket.xml \

make-directive-index.py

@@ -66,6 +66,23 @@ TEMPLATE = '''\
                 <variablelist id='systemd-directives' />
         </refsect1>
 
+        <refsect1>
+                <title>Options on the kernel command line</title>
+
+                <para>Kernel boot options for configuring the behaviour of the
+                systemd process.</para>
+
+                <variablelist id='kernel-commandline-directives' />
+        </refsect1>
+
+        <refsect1>
+                <title>Environment variables</title>
+
+                <para>Environment variables understood by the systemd process.</para>
+
+                <variablelist id='environment-variables' />
+        </refsect1>
+
         <refsect1>
                 <title>UDEV directives</title>
 

man/systemd.xml

@@ -877,7 +877,7 @@
         <refsect1>
                 <title>Environment</title>
 
-                <variablelist>
+                <variablelist class='environment-variables'>
                         <varlistentry>
                                 <term><varname>$SYSTEMD_LOG_LEVEL</varname></term>
                                 <listitem><para>systemd reads the
@@ -987,7 +987,7 @@
                 <filename>/proc/cmdline</filename>
                 instead.</para></footnote>:</para>
 
-                <variablelist>
+                <variablelist class='kernel-commandline-directives'>
                         <varlistentry>
                                 <term><varname>systemd.unit=</varname></term>
                                 <term><varname>rd.systemd.unit=</varname></term>