do not hardcode chapter numbers in General Compilation Instructions

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@11962 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

part3intro/generalinstructions.xml

@@ -94,7 +94,8 @@
           <orderedlist numeration="loweralpha" spacing="compact">
             <listitem>
               <para>Using the <command>tar</command> program, extract the package
-              to be built.  In Chapters 5 and 6, ensure you are 
+              to be built.  In <xref linkend="chapter-cross-tools"/> and
+              <xref linkend="chapter-temporary-tools"/>, ensure you are 
               the <emphasis>lfs</emphasis> user when extracting the package.</para>
             </listitem>
             <listitem>