[patch] inform porters handbook about INSTALL_KLD

Describe the INSTALL_KLD command in the Porters Handbook

PR:		docs/116989
Submitted by:	Edwin Groothuis <edwin@mavetju.org>
Approved by:	Remko Lodder <remko@elvandar.org>

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

@@ -4110,6 +4110,13 @@ PORTVERSION=   1.0</programlisting>
 	      executable scripts.</para>
 	  </listitem>
 
+	  <listitem>
+	    <para><makevar>INSTALL_KLD</makevar> is a command to install
+	      kernel loadable modules. Some architectures don't like it when
+	      the modules are stripped, therefor use this command instead
+	      of <makevar>INSTALL_PROGRAM</makevar>.</para>
+	  </listitem>
+
 	  <listitem>
 	    <para><makevar>INSTALL_DATA</makevar> is a command to install
 	      sharable data.</para>