Using perl:

- suggest using module hierarchy on cpan.org master site

PR:		docs/99554 (adapted from)
Submitted by:	clsung

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

@@ -4561,6 +4561,19 @@ PORTVERSION=   1.0</programlisting>
     <sect1 id="using-perl">
       <title>Using <literal>perl</literal></title>
 
+      <para>If <makevar>MASTER_SITES</makevar> is set to
+	<makevar>MASTER_SITE_PERL_CPAN</makevar>, then preferred value of
+	<makevar>MASTER_SITE_SUBDIR</makevar> is top-level hierarchy name.
+	For example, the recommend value for <literal>p5-Module-Name</literal>
+	is <literal>Module</literal>.  The top-level hierarchy can be examined
+	at <ulink url="http://cpan.org/modules/by-module/">cpan.org</ulink>.
+	This keeps the port working when the author of the module
+	changes.</para>
+
+      <para>The exception to this rule is when the relevant directory does not
+	exist.  In such case, using author's id as
+	<makevar>MASTER_SITE_SUBDIR</makevar> is allowed.</para>
+
       <table frame="none">
 	<title>Variables for ports that use <literal>perl</literal></title>