getallheaders() is not available in nginx

It seems that the getallheaders() function is not available when running php-fpm and nginx. This issue has been encountered on other projects.

• Panels Ajax Tabs: #2110907: Fatal error: Call to undefined function getallheaders() in panels_ajax_tab.module line 96
• CORS: #2200567: Fatal error, call to undefined function getallheaders() on nginx

It seems like what they did in CORS should solve this: https://www.drupal.org/files/issues/2200567_getallheaders.patch