gcc: remove the errorenous header for 32-bit correctly

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@11654 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter06/gcc.xml

@@ -155,7 +155,7 @@ su nobody -s /bin/bash -c "PATH=$PATH make -k check"</userinput></screen>
     <para>Install the package and remove an unneeded directory:</para>
 
 <screen><userinput remap="install">make install
-rm -rf /usr/lib/gcc/x86_64-pc-linux-gnu/9.1.0/include-fixed/bits/</userinput></screen>
+rm -rf /usr/lib/gcc/$(gcc -dumpmachine)/9.1.0/include-fixed/bits/</userinput></screen>
 
     <para>Create a symlink required by the <ulink
     url="https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch03s09.html">FHS</ulink>