Force show 3 dot overflow menu item on ActionBar via menu.xml

gistfile1.txt

<item
        android:id="@+id/menu_overflow"
        android:title="Overflow"
        android:icon="@android:drawable/ic_menu_more"
        android:orderInCategory="1"
        app:showAsAction="always">
        <menu>
            <item android:id="@+id/item1"
                android:icon="@drawable/icon1"
                android:title="title1"
                app:showAsAction="never"/>
            <item android:id="@+id/item2"
                android:icon="@drawable/icon2"
                android:title="title2"
                app:showAsAction="never"/>
        </menu>
    </item>