Added a grep and sed to fix compiling against some recent versions of glibc

git-svn-id: svn://svn.linuxfromscratch.org/BLFS/trunk/BOOK@6067 af4574ff-66df-0310-9fd7-8a98e5e911e0

x/installing/xfree86.xml

@@ -175,6 +175,29 @@
     <title>Installation of XFree86</title>
 
     <sect3>
+      <title>Glibc build fix</title>
+
+<!-- To be removed if/when proposed glibc patch is added to LFS SVN
+     Leave in in for a couple of weeks with 'you may need' and a testcase
+     around it to save the support list silly questions.  Should remove in
+     a couple of weeks -->
+      <para>Xfree86 may have a problem with <filename>sys/kd.h</filename>
+      installed with some recent versions of <application>Glibc</application>.
+      This has recently been fixed in LFS SVN.  Execute the
+      following commands to work around a broken <filename>kd.h</filename>
+      file. The <command>grep</command> command is to ensure the modification
+      is only made if it is needed. Run these commands from within the
+      <filename class="directory">xc</filename> folder:</para>
+
+<screen><userinput>grep "__undef_LINUX" \
+    /usr/include/sys/kd.h 2&gt;&amp;1 &gt; /dev/null || \
+    sed -i.bak '/X.h/i #include &lt;linux/types.h&gt;' \
+    programs/Xserver/hw/xfree86/os-support/linux/lnx_agp.c</userinput></screen>
+<!-- End remove -->
+
+    </sect3>
+    <sect3>
+
       <title>Setting Up a Shadow Directory</title>
 
       <para>When building <application>XFree86</application>, you should create