Added a test for mb_send_mail() to check if the simplified Chinese support

works

ext/mbstring/tests/mb_send_mail05.phpt

@@ -0,0 +1,39 @@
+--TEST--
+mb_send_mail() test 5 (lang=Simplified Chinese)
+--SKIPIF--
+<?php
+if (@mb_send_mail() === false || !mb_language("Simplified Chinese")) {
+	die("skip mb_send_mail() not available");
+}
+?>
+--INI--
+sendmail_path=cat
+--FILE--
+<?php
+$to = 'example@example.com';
+
+/* default setting */
+mb_send_mail($to, mb_language(), "test");
+
+/* Simplified Chinese (HK-GB-2312) */
+if (mb_language("simplified chinese")) {
+	mb_internal_encoding('GB2312');
+	mb_send_mail($to, "²âÑé ".mb_language(), "²âÑé");
+}
+?>
+--EXPECTF--
+To: example@example.com
+Subject: %s
+Mime-Version: 1.0
+Content-Type: text/plain; charset=%s
+Content-Transfer-Encoding: %s
+
+test
+To: example@example.com
+Subject: =?HZ-GB-2312?B?fnsyYlFpfn0gU2ltcGxpZmllZCBD?=
+ =?HZ-GB-2312?B?aGluZXNl?=
+Mime-Version: 1.0
+Content-Type: text/plain; charset=HZ-GB-2312
+Content-Transfer-Encoding: 7bit
+
+~{2bQi~}