gistfile1.php

<?php

function taleo_libraries_info() {
  return array(
    'Taleo' => array(
      'name' => 'Taleo PHP Library',
      'xautoload' => '_taleo_xautoload',
    ),
  );
}

function _taleo_xautoload($api) {
  // Load Guzzle
  $api->namespaceRoot('Guzzle\Http', 'vendor/guzzle/guzzle/src');
  $api->namespaceRoot('Guzzle\Http\Curl', 'vendor/guzzle/guzzle/src');
  $api->namespaceRoot('Guzzle\Service', 'vendor/guzzle/guzzle/src');
  $api->namespaceRoot('Guzzle\Common', 'vendor/guzzle/guzzle/src');
  $api->namespaceRoot('Guzzle\Parser', 'vendor/guzzle/guzzle/src');

  // Load Symfony Event Dispatcher
  $api->namespaceRoot('Symfony\Component\EventDispatcher', 'vendor/symfony/event-dispatcher');

  // Load Monolog
  $api->namespaceRoot('Monolog', 'vendor/monolog/monolog/src');

  // Load Taleo
  $api->namespaceRoot('Taleo\Main', 'src');
}


/**
 * Helper function to get all jobs from the Taleo database.
 */
function _taleo_getjobs() {

  // Load required procedural code.
  _taleo_init();

  //libraries_get_path('Taleo');
  // returns 'sites/all/libraries/Taleo' (which is good)

  $orgCode = variable_get('taleo_company_code', '');
  $user = variable_get('taleo_username', '');
  $password = variable_get('taleo_password', '');

  $taleo = new \Taleo\Main\Taleo($user, $password, $orgCode);
  $taleo->login();
}

/**
 * Function name should not nameclash with hook_init()
 */
function _taleo_init() {
  $path = libraries_get_path('Taleo');
  // Include some procedural code.
  require_once $path . '/vendor/guzzle/guzzle/src/...';
}

// This returns an error:
//   Fatal error: Call to undefined function Guzzle\Http\Curl\curl_version()
//   in C:\cygwin\home\DELLAIEP\www\jobs.localhost\sites\all\libraries\Taleo\vendor\guzzle\guzzle\src\Guzzle\Http\Curl\CurlVersion.php on line 47

I see ! :)