Explain with-glibc-version in gcc pass 1

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@11753 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter05/gcc-pass1.xml

@@ -152,6 +152,15 @@ cd       build</userinput></screen>
     <variablelist>
       <title>The meaning of the configure options:</title>
 
+      <varlistentry>
+        <term><parameter>--with-glibc-version=2.11</parameter></term>
+        <listitem>
+          <para>This option ensures the package will be compatible with the host's
+          version of glibc.  It is set to the minimum glibc requirement 
+          specified in the <xref linkend="ch-partitioning-hostreqs"/>.</para>
+        </listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><parameter>--with-newlib</parameter></term>
         <listitem>