Remove description of PKG_CONFIG variables that are no longer used in Man-DB.

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@9896 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter06/man-db.xml

@@ -55,15 +55,6 @@
     <variablelist>
       <title>The meaning of the configure options:</title>
 
-      <varlistentry>
-        <term><parameter>PKG_CONFIG=, libpipeline_ ...</parameter></term>
-        <listitem>
-          <para>These environment variables allow the configuration 
-          process to complete without the external <command>pkg-config</command> 
-          program.</para>
-        </listitem>
-      </varlistentry>
-
       <varlistentry>
         <term><parameter>--disable-setuid</parameter></term>
         <listitem>