Making user mail available in user-profile.tpl.php via template.php – Drupal 7

template.php

<?php
/**
 * Process variables for user-profile.tpl.php.
 *
 * The $variables array contains the following arguments:
 * - $account
 *
 * @see user-profile.tpl.php
 */
function YOUR_THEMENAME_preprocess_user_profile(&$variables) {
  $account = $variables['elements']['#account'];
  // Helpful $user_profile variable for templates.
  foreach (element_children($variables['elements']) as $key) {
    $variables['user_profile'][$key] = $variables['elements'][$key];
  }
  //Add mail to $user_profile variable
  $variables['user_profile']['mail'] = $account->mail;
  // Preprocess fields.
  field_attach_preprocess('user', $account, $variables['elements'], $variables);
}
?>

Thanks to https://www.drupal.org/node/1161236#comment-6163514