ref-manual, mega-manual: Updated "SDK Generation" section.

Updated the figure used to show SDK generation.  I added a block
to cover the extensible SDK stuff.  This affected the figures
folder in both the ref-manual and the mega-manual.

Updated the text section to support the new figure.

(From yocto-docs rev: b9fd7c2b0ea0e2fe1805a1bb1eb1bcb82c807b66)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/closer-look.xml

@@ -1150,8 +1150,9 @@
 
             <para>
                 The OpenEmbedded build system uses BitBake to generate the
-                Software Development Kit (SDK) installer script:
-                <imagedata fileref="figures/sdk-generation.png" align="center" width="6in" depth="7in" />
+                Software Development Kit (SDK) installer script for both the
+                standard and extensible SDKs:
+                <imagedata fileref="figures/sdk-generation.png" align="center" />
             </para>
 
             <note>
@@ -1163,14 +1164,16 @@
                 cross-development toolchain using the
                 <link linkend='ref-tasks-populate_sdk'><filename>do_populate_sdk</filename></link>
                 task, see the
-                "<ulink url='&YOCTO_DOCS_ADT_URL;#optionally-building-a-toolchain-installer'>Optionally Building a Toolchain Installer</ulink>"
-                section in the Yocto Project Application Developer's Guide.
+                "<ulink url='&YOCTO_DOCS_SDK_URL;#sdk-optionally-building-a-toolchain-installer'>Optionally Building a Toolchain Installer</ulink>"
+                section in the Yocto Project Software Development Kit (SDK)
+                Developer's Guide.
             </note>
 
             <para>
                 Like image generation, the SDK script process consists of
                 several stages and depends on many variables.
-                The <filename>do_populate_sdk</filename> task uses these
+                The <filename>do_populate_sdk</filename> and
+                <filename>do_populate_sdk_ext</filename> tasks use these
                 key variables to help create the list of packages to actually
                 install.
                 For information on the variables listed in the figure, see the
@@ -1179,8 +1182,9 @@
             </para>
 
             <para>
-                The <filename>do_populate_sdk</filename> task handles two
-                parts: a target part and a host part.
+                The <filename>do_populate_sdk</filename> task helps create
+                the standard SDK and handles two parts: a target part and a
+                host part.
                 The target part is the part built for the target hardware and
                 includes libraries and headers.
                 The host part is the part of the SDK that runs on the
@@ -1188,16 +1192,19 @@
             </para>
 
             <para>
-                Once both parts are constructed, the
-                <filename>do_populate_sdk</filename> task performs some cleanup
-                on both parts.
-                After the cleanup, the task creates a cross-development
-                environment setup script and any configuration files that
-                might be needed.
+                The <filename>do_populate_sdk_ext</filename> task helps create
+                the extensible SDK and handles host and target parts
+                differently than its counter part does for the standard SDK.
+                For the extensible SDK, the task encapsulates the build system,
+                which includes everything needed (host and target) for the SDK.
             </para>
 
             <para>
-                The final output of the task is the Cross-development
+                Regardless of the type of SDK being constructed, the
+                tasks perform some cleanup after which a cross-development
+                environment setup script and any needed configuration files
+                are created.
+                The final output is the Cross-development
                 toolchain installation script (<filename>.sh</filename> file),
                 which includes the environment setup script.
             </para>