idn_to_ascii is only used if available

lib/private/mail.php

@@ -137,6 +137,9 @@ class OC_Mail {
 	 * @return string
 	 */
 	public static function buildAsciiEmail($emailAddress) {
+		if (!function_exists('idn_to_ascii')) {
+			return $emailAddress;
+		}
 
 		list($name, $domain) = explode('@', $emailAddress, 2);
 		$domain = idn_to_ascii($domain);

tests/lib/mail.php

@@ -8,6 +8,15 @@
 
 class Test_Mail extends PHPUnit_Framework_TestCase {
 
+	protected function setUp()
+	{
+		if (!function_exists('idn_to_ascii')) {
+			$this->markTestSkipped(
+				'The intl extension is not available.'
+			);
+		}
+	}
+
 	/**
 	 * @dataProvider buildAsciiEmailProvider
 	 * @param $expected