theme-settings.php

<?php
// Include the definition of zen_settings() and zen_theme_get_default_settings().
include_once './' . drupal_get_path('theme', 'zen') . '/theme-settings.php';


/**
 * Implementation of THEMEHOOK_settings() function.
 *
 * @param $saved_settings
 *   An array of saved settings for this theme.
 * @return
 *   A form array.
 */
function sitetheme_settings($saved_settings) {

  // Get the default values from the .info file.
  $defaults = zen_theme_get_default_settings('sitetheme');

  // Merge the saved variables and their default values.
  $settings = array_merge($defaults, $saved_settings);

  /*
   * Create the form using Forms API: http://api.drupal.org/api/6
   */
  $form = array();
  /* -- Delete this line if you want to use this setting
  $form['sitetheme_example'] = array(
    '#type'          => 'checkbox',
    '#title'         => t('Use this sample setting'),
    '#default_value' => $settings['sitetheme_example'],
    '#description'   => t("This option doesn't do anything; it's just an example."),
  );
  // */

  $form['support']['zen_html5_respond_meta'] = array(
    '#type'          => 'checkboxes',
    '#title'         => t('Add HTML5 and responsive scripts and meta tags to every page.'),
    '#default_value' => theme_get_setting('zen_html5_respond_meta'),
    '#options'       => array(
                          'respond' => t('Add Respond.js JavaScript to add basic CSS3 media query support to IE 6-8.'),
                          'html5' => t('Add HTML5 shim JavaScript to add support to IE 6-8.'),
                          'meta' => t('Add meta tags to support responsive design on mobile devices.'),
                        ),
    '#description'   => t('IE 6-8 require a JavaScript polyfill solution to add basic support of HTML5 and CSS3 media queries. If you prefer to use another polyfill solution, such as <a href="!link">Modernizr</a>, you can disable these options. Respond.js only works if <a href="@url">Aggregate CSS</a> is enabled. Mobile devices require a few meta tags for responsive designs.', array('!link' => 'http://www.modernizr.com/', '@url' => url('admin/config/development/performance'))),
  );

  // Add the base theme's settings.
  $form += zen_settings($saved_settings, $defaults);

  // Remove some of the base theme's settings.
  unset($form['themedev']['zen_layout']); // We don't need to select the base stylesheet.

  // Return the form
  return $form;
}