Add role="nodump" to examples in "About SBUs"

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@11468 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter04/aboutsbus.xml

@@ -43,11 +43,11 @@
     <command>make</command> program how many processors are available.  For
     instance, a Core2Duo can support two simultaneous processes with:</para>
 
-    <screen><userinput>export MAKEFLAGS='-j 2'</userinput></screen>
+    <screen role="nodump"><userinput>export MAKEFLAGS='-j 2'</userinput></screen>
 
     <para>or just building with:</para>
 
-    <screen><userinput>make -j2</userinput></screen>
+    <screen role="nodump"><userinput>make -j2</userinput></screen>
 
     <para>When multiple processors are used in this way, the SBU units in the
     book will vary even more than they normally would.  In some cases, the make