gistfile1.txt

this is 7.0 ok. 
// make child theme inherit all of Tempera's external WP options (header/bg/menus/widgets)
if ( get_stylesheet() !== get_template() ) {
		add_filter(
			'pre_update_option_theme_mods_' . get_stylesheet(),
			function ( $value, $old_value ) {
				update_option( 'theme_mods_' . get_template(), $value );
				return $old_value; // prevent update to child theme mods
			},
			10,
		2 );
		add_filter( 'pre_option_theme_mods_' . get_stylesheet(), function ( $default ) {
			return get_option( 'theme_mods_' . get_template(), $default );
		} );
};