Added a brief explanation of the Linux API Headers instructions.

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@8708 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter01/changelog.xml

@@ -39,6 +39,10 @@
     <listitem>
       <para>2008-10-27</para>
       <itemizedlist>
+        <listitem>
+          <para>[bdubbs] - Added a brief explanation of the Linux API Headers
+          instructions.</para>
+        </listitem>
         <listitem>
           <para>[bdubbs] - Added i386, linux32, and linux64 as symbolic 
           links to setarch in util-linux contents.</para>

chapter05/linux-headers.xml

@@ -44,14 +44,21 @@
     <title>Installation of Linux API Headers</title>
 
     <para>The Linux kernel needs to expose an Application Programming Interface
-    (API) for the system's C library (Glibc in LFS) to utilize.  This is done
+    (API) for the system's C library (Glibc in LFS) to use.  This is done
     by way of sanitizing various C header files that are shipped in the Linux
     kernel source tarball.</para>
 
-    <para>Install the header files:</para>
+    <para>First, make sure there are no stale files and dependencies lying around
+    from previous activity:</para>
 
-<screen><userinput remap="install">make mrproper
-make headers_check
+<screen><userinput remap="install">make mrproper</userinput></screen>
+
+    <para>Now test and extract the user-visible kernel headers from the source.
+    They are placed in an intermediate local directory and copied to the needed
+    location because the extraction process removes any existing files in 
+    the target directory.</para>
+
+<screen><userinput remap="install">make headers_check
 make INSTALL_HDR_PATH=dest headers_install
 cp -rv dest/include/* /tools/include</userinput></screen>
 

chapter06/linux-headers.xml

@@ -42,14 +42,21 @@
     <title>Installation of Linux API Headers</title>
 
     <para>The Linux kernel needs to expose an Application Programming Interface
-    (API) for the system's C library (Glibc in LFS) to utilize.  This is done
+    (API) for the system's C library (Glibc in LFS) to use.  This is done
     by way of sanitizing various C header files that are shipped in the Linux
     kernel source tarball.</para>
 
-    <para>Install the header files:</para>
+    <para>First, make sure there are no stale files and dependencies lying around
+    from previous activity:</para>
 
-<screen><userinput remap="install">make mrproper
-make headers_check
+<screen><userinput remap="install">make mrproper</userinput></screen>
+
+    <para>Now test and extract the user-visible kernel headers from the source.
+    They are placed in an intermediate local directory and copied to the needed
+    location because the extraction process removes any existing files in 
+    the target directory.</para>
+
+<screen><userinput remap="install">make headers_check
 make INSTALL_HDR_PATH=dest headers_install
 cp -rv dest/include/* /usr/include</userinput></screen>