PR: docs/150124

Fix/Update the instructions on "how to build a custom kernel".

- The fact that you need the whole source tree for this is well hidden at the moment.
- The instructions on how to extract the src tree from a CD are wrong (changed pathnames).
- In order to extract the full src tree you would need 20 cat/tar commands.  So remove that part.
- While here do some additional rewording.

Noticed by:     Jared (blahbleh666 ett hotmail dott com)

en_US.ISO8859-1/books/handbook/kernelconfig/chapter.sgml

@@ -266,6 +266,11 @@ following line in &man.loader.conf.5:
       <secondary>building / installing</secondary>
     </indexterm>
 
+    <note>
+      <para>It is required to have the full &os; source tree installed
+	to build the kernel.</para>
+    </note>
+
     <para>First, let us take a quick tour of the kernel build directory.
       All directories mentioned will be relative to the main
       <filename>/usr/src/sys</filename> directory, which is also
@@ -287,35 +292,26 @@ following line in &man.loader.conf.5:
       directory structure, with each supported device, file system, and
       option in its own subdirectory.</para>
 
-    <para>This chapter assumes that you are using the i386 architecture
-      in the examples.  If this is not the case for your situation,
-      make appropriate adjustments to the path names for your system's
-      architecture.</para>
+    <para>The examples in this chapter assume that you are using the i386
+      architecture.  If your system has a different architecture you need
+      to change the path names accordingly.</para>
 
     <note>
-      <para>If there is <emphasis>not</emphasis> a
-	<filename>/usr/src/sys</filename> directory on your system,
-	then the kernel source has not been installed.  The easiest
-	way to do this is by running
-	<command>sysinstall</command> as
-	<username>root</username>, choosing
+      <para>If the directory <filename>/usr/src/</filename> does not
+	exist on your system (or if it is empty), then the sources have
+	not been installed.  The easiest way to install the full source
+	tree is is to run <command>sysinstall</command> as
+	<username>root</username>, and then choosing
 	<guimenuitem>Configure</guimenuitem>, then
 	<guimenuitem>Distributions</guimenuitem>, then
-	<guimenuitem>src</guimenuitem>, then
-	<guimenuitem>base</guimenuitem> and
-	<guimenuitem>sys</guimenuitem>.  If you have an aversion to
-	<application>sysinstall</application> and you have access to
-	an <quote>official</quote> &os; CDROM, then you can also
-	install the source from the command line:</para>
+	<guimenuitem>src</guimenuitem>, and finally
+	<guimenuitem>All</guimenuitem>.  If it does not exist, you should
+	also create a symlink to <filename>/usr/src/sys/</filename>:</para>
 
-      <screen>&prompt.root; <userinput>mount /cdrom</userinput>
-&prompt.root; <userinput>mkdir -p /usr/src/sys</userinput>
-&prompt.root; <userinput>ln -s /usr/src/sys /sys</userinput>
-&prompt.root; <userinput>cat /cdrom/src/ssys.[a-d]* | tar -xzvf -</userinput>
-&prompt.root; <userinput>cat /cdrom/src/sbase.[a-d]* | tar -xzvf -</userinput></screen>
+	<screen>&prompt.root; <userinput>ln -s /usr/src/sys/ /sys/</userinput></screen>
     </note>
 
-    <para>Next, move to the
+    <para>Next, change to the
       <filename><replaceable>arch</replaceable>/conf</filename> directory
       and copy the <filename>GENERIC</filename> configuration file to the
       name you want to give your kernel.  For example:</para>
@@ -392,6 +388,11 @@ following line in &man.loader.conf.5:
     <procedure>
       <title>Building a Kernel</title>
 
+      <note>
+	<para>It is required to have the full &os; source tree installed
+	  to build the kernel.</para>
+      </note>
+
       <step>
 	<para>Change to the <filename
 	  class="directory">/usr/src</filename> directory:</para>
@@ -412,11 +413,6 @@ following line in &man.loader.conf.5:
       </step>
     </procedure>
 
-    <note>
-      <para>It is required to have full &os; source tree to build the
-	kernel.</para>
-    </note>
-
     <tip>
       <para>By default, when you build a custom kernel,
 	<emphasis>all</emphasis> kernel modules will be rebuilt as well.