- Document dependencies with minimal version of dependent package

svn path=/head/; revision=26873

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

@@ -3389,6 +3389,22 @@ ALWAYS_KEEP_DISTFILES=  yes
 
 	</sect2>
 
+	<sect2>
+	  <title>Minimal version of a dependency</title>
+
+	  <para>A minimal version of a dependency can be specified in any
+	    <makevar>*_DEPENDS</makevar> variable using the following
+	    syntax:</para>
+
+	  <programlisting>p5-Spiffy>=0.26:${PORTSDIR}/devel/p5-Spiffy</programlisting>
+
+	  <para>The first field contains a dependent package name,
+	    which must match the entry in the package database,
+	    a comparison sign, and a package version.  The dependency
+	    is satisfied if p5-Spiffy-0.26 or newer is installed on
+	    the machine.</para>
+	</sect2>
+
 	<sect2>
 	  <title>Notes on dependencies</title>