Add IE conditional html5 shim to header

wps_add_ie_html5_shim.php

<?php
add_action( 'wp_head', 'wps_add_ie_html5_shim' );
/**
 *  Add IE conditional html5 shim to header
 */
function wps_add_ie_html5_shim() {
    global $is_IE;
    if ( $is_IE ) {
        echo '<!--[if lt IE 9]>';
        echo '<script src="http://html5shim.googlecode.com/svn/trunk/html5.js"></script>';
        echo '<![endif]-->';
    }
}