Restore comment about possible math failures in glibc

git-svn-id: svn://svn.linuxfromscratch.org/LFS/trunk/BOOK@11421 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter06/glibc.xml

@@ -217,13 +217,13 @@ unset GCC_INCDIR</userinput></screen>
         fail.  The reason is not completely understood, but indications are
         that minor timing issues can trigger these failures.</para>
       </listitem>
-
+-->
       <listitem>
         <para>The math tests sometimes fail when running on
         systems where the CPU is not a relatively new Intel or
         AMD processor.</para>
       </listitem>
-
+<!--
       <listitem>
         <para>The
         <emphasis>nptl/tst-thread-affinity-{pthread,pthread2,sched}</emphasis>