Explanation update (included /dev/null)

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@407 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter06/glibc-exp.xml

@@ -1,6 +1,12 @@
 <sect2>
 <title>Command explanations</title>
 
+<para>
+<userinput>mknod -m 0666 /dev/null c 1 3:</userinput> Glibc needs a
+null device to compile properly. All other devices will be created in the
+next section.
+</para>
+
 <para>
 <userinput>touch /etc/ld.so.conf</userinput> One of the final steps of
 the Glibc installation is running ldconfig to update the dynamic loader