replace old x86_64 triplets

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@12160 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter08/binutils.xml

@@ -136,7 +136,7 @@ cd       build</userinput></screen>
           ultimately be located) is set to <filename
           class="directory">$(exec_prefix)/$(target_alias)</filename>. For
           example, x86_64 machines would expand that to <filename
-          class="directory">/usr/x86_64-unknown-linux-gnu</filename>. Because this is
+          class="directory">/usr/x86_64-pc-linux-gnu</filename>. Because this is
           a custom system, this target-specific directory in <filename
           class="directory">/usr</filename> is not required. <filename
           class="directory">$(exec_prefix)/$(target_alias)</filename> would be

chapter08/gmp.xml

@@ -106,7 +106,7 @@ make html</userinput></screen>
     the system capabilities and there will be errors in the tests or other
     applications using the gmp libraries with the message "Illegal
     instruction".  In this case, gmp should be reconfigured with the option
-    --build=x86_64-unknown-linux-gnu and rebuilt.</para></caution>
+    --build=x86_64-pc-linux-gnu and rebuilt.</para></caution>
 
     <para>Ensure that all 197 tests in the test suite passed.
     Check the results by issuing the following command:</para>