fix explanation

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@1520 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter05/patch-exp.xml

@@ -1,8 +1,8 @@
 <sect2>
 <title>Command explanations</title>
 
-<para><userinput>CPPFLAGS="$CPPFLAGS -D_GNU_SOURCE": </userinput>
-Adding <userinput>-D_GNU_SOURCE</userinput> command before
+<para><userinput>CPPFLAGS=-D_GNU_SOURCE: </userinput>
+Adding <userinput>-D_GNU_SOURCE</userinput> to CPPFLAGS command before
 we configure patch fixes installation of the package on PPC and m68k
 platforms (that we know of).  It also doesn't hurt compilation on other
 platforms (such as x86) so we do it by default.</para>