mattg888/GCM-PHP-Server-Push-Message — pull request #3 by diegodepablos (2014-09-24 10:36:34+00:00)
Title: Update GCMPushMessage.php

I had problems using the library as is, I had to add these two lines to make it work:

curl_setopt( $ch, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt( $ch, CURLOPT_SSL_VERIFYPEER, false);