update git submodules on autogen

Update the submodules (currently starksoftproxy) when ./autogen.sh is run.

autogen.sh

@@ -79,6 +79,13 @@ $AUTOMAKE --add-missing --gnu $am_opt
 echo "Running $AUTOCONF ..."
 $AUTOCONF
 
+if test x$NOGIT = x; then
+    git submodule init || exit 1
+    git submodule update || exit 1
+else
+    echo Skipping git submodule initialization.
+fi
+
 if test x$NOCONFIGURE = x; then
     echo Running $srcdir/configure $conf_flags "$@" ...
     $srcdir/configure --enable-maintainer-mode $conf_flags "$@" || exit 1