Update explanatory text for GCC's --with-arch parameter

git-svn-id: http://svn.linuxfromscratch.org/LFS/branches/jh/BOOK@8363 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter01/changelog.xml

@@ -39,6 +39,9 @@
     <listitem>
       <para>2007-08-31</para>
       <itemizedlist>
+        <listitem>
+          <para>[jhuntwork] - Update explanatory text for GCC's --with-arch parameter.</para>
+        </listitem>
         <listitem>
           <para>[jhuntwork] - Add --disable-bootstrap flags to GCC pass 2 and chapter 6 GCC,
           to achieve traditional LFS build methods with GCC 4.2.1.</para>

chapter05/gcc-pass1.xml

@@ -110,9 +110,17 @@ unset M64 WITHARCH</userinput></screen>
       <varlistentry>
         <term><parameter>--with-arch=i486</parameter></term>
         <listitem>
-    	  <para>On x86 machines Glibc needs to be built for a minimum architecture
-	  of <quote>i486</quote>. Setting this for the GCC build ensures that the
-	  entire system is built consistently.</para>
+    	  <para>On x86 machines Glibc-&glibc-version; needs to be built for a
+	  minimum architecture of <quote>i486</quote>. In fact, Glibc developers suggest
+	  setting the compiler flag <parameter>-march=i486</parameter> when compiling it.
+	  However, by using the above parameter for the GCC build, we can set a default
+	  value for <parameter>-march</parameter> at the compiler level, ensuring that
+	  the entire system is built consistently, i.e., for the same cpu-type.
+	  Of course, values greater or more specific than <quote>i486</quote> could be
+	  used. See <command>man gcc</command> for other acceptable cpu-types.
+	  Keep in mind that using an incompatible cpu-type for the machine will result
+	  in breakage. The advantage of <quote>i486</quote> is that it is a generic
+	  option and will work for all modern x86 machines.</para>
         </listitem>
       </varlistentry>