add xreflabel gcc-pass2, to be consistent with gcc-pass1

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@11967 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter06/gcc-pass2.xml

@@ -5,7 +5,7 @@
   %general-entities;
 ]>
 
-<sect1 id="ch-tools-gcc-pass2" role="wrap">
+<sect1 id="ch-tools-gcc-pass2" role="wrap" xreflabel="gcc-pass2">
   <?dbhtml filename="gcc-pass2.html"?>
 
   <sect1info condition="script">