sdk-manual: Updated configure.ac file in helloworld example.

The file was named 'configure.in' and was slightly different than
what it needed to be in order to work.  The file needs to be named
'configure.ac' and have slightly different contents.  Fixed both.

(From yocto-docs rev: 1b80e90848d23737462f8b0e55b2ff604f9abf41)

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

documentation/sdk-manual/sdk-using.xml

@@ -226,7 +226,7 @@
                     </literallayout></para></listitem>
                 <listitem><para><emphasis>Populate the directory:</emphasis>
                     Create <filename>hello.c</filename>, <filename>Makefile.am</filename>,
-                    and <filename>configure.in</filename> files as follows:
+                    and <filename>configure.ac</filename> files as follows:
                     <itemizedlist>
                         <listitem><para>For <filename>hello.c</filename>, include
                             these lines:
@@ -247,8 +247,8 @@
                         <listitem><para>For <filename>configure.in</filename>,
                             include these lines:
                             <literallayout class='monospaced'>
-     AC_INIT(hello.c)
-     AM_INIT_AUTOMAKE(hello,0.1)
+     AC_INIT(hello,0.1)
+     AM_INIT_AUTOMAKE([foreign])
      AC_PROG_CC
      AC_PROG_INSTALL
      AC_OUTPUT(Makefile)