AJP connector with external authentication

Tomcat allows to set the tomcatAuthentication attribute of the AJP connector to false to allow external web servers (e.g. apache httpd) to handle the authentication and pass that along.
A similar option was added recently to JBossWeb as well (see WFLY-254), but JBossWeb has been replaced by Undertow. With Undertow this option isn't available as far as I can see.
For me this is a critical problem as there is currently no way I can do negotiated (SPNEGO) authentication from within WildFly+Undertow. (See also WFLY-2404).