Update for USES=kmod, most notably:

- simplify the part on staging kernel module ports
- rewrite the parts on checking for kernel sources

Approved by:	remko (mentor)

en_US.ISO8859-1/books/porters-handbook/book.xml

@@ -2225,7 +2225,10 @@ PORTEPOCH=	1</programlisting>
 	  <listitem>
 	    <para>Ports which install loadable kernel modules should
 	      have the virtual category <filename>kld</filename> in
-	      their <varname>CATEGORIES</varname> line.</para>
+	      their <varname>CATEGORIES</varname> line.  This is one
+	      of the things handled automatically by adding
+	      <literal>kmod</literal> to the <varname>USES</varname>
+	      line.</para>
 	  </listitem>
 
 	  <listitem>
@@ -5322,27 +5325,8 @@ PORTVERSION=	1.0</programlisting>
 
       <para>Ports that install kernel modules must prepend the
 	<varname>STAGEDIR</varname> variable to
-	their default destination, <filename>/boot/modules</filename>.  Then the
-	<buildtarget>pre-install</buildtarget> target can be used to handle
-	the creation of this directory:</para>
-
-      <programlisting>pre-install:
-	${MKDIR} ${STAGEDIR}/boot/modules</programlisting>
-
-      <para>&man.kldxref.8; should not be run when installing to
-	the temporary staging directory.  To prevent this, define
-	the<varname>NO_XREF</varname> variable and add it
-	to <varname>MAKE_ENV</varname> in the port's
-	<filename>Makefile</filename>:</para>
-
-      <programlisting>MAKE_ENV+=	KMODDIR=/boot/modules NO_XREF=yes</programlisting>
-      <para>The hints files for the kernel loader should
-	be regenerated only when the package is installed or
-	deinstalled.  Do this by invoking &man.kldxref.8; from
-	<filename>pkg-plist</filename>:</para>
-
-      <programlisting>@unexec kldxref /boot/modules
-@exec kldxref /boot/modules</programlisting>
+	their destination, by default
+	<filename>/boot/modules</filename>.</para>
     </sect1>
 
     <sect1 xml:id="porting-shlibs">
@@ -10046,9 +10030,11 @@ GROUPS=	pulse pulse-access pulse-rt</programlisting>
 	correct way to determine if the user has them
 	installed:</para>
 
-      <programlisting>.if !exists(${SRC_BASE}/sys/Makefile)
-IGNORE=	requires kernel sources to be installed
-.endif</programlisting>
+      <programlisting>USES=	kmod</programlisting>
+
+      <para>Apart from this check, the <literal>kmod</literal> feature
+	takes care of most items that these ports need to take into
+	account.</para>
     </sect1>
   </chapter>
 
@@ -11988,11 +11974,6 @@ exec %%LOCALBASE%%/bin/java -jar %%DATADIR%%/foo.jar "$@"</programlisting>
 		  &os;</para>
 	      </listitem>
 
-	      <listitem>
-		<para>requires &os; kernel sources to build, but the
-		  user does not have them installed</para>
-	      </listitem>
-
 	      <listitem>
 		<para>has a distfile which may not be automatically
 		  fetched due to licensing restrictions</para>