Apache 2.4 not working with mod_auth_kerb2

[clpollock]

Hello, I've been trying to use Kerberos authentication with Apache 2.4, but it fails on startup with the following error:

Performing sanity check on apache24 configuration:
httpd: Syntax error on line 154 of /usr/local/etc/apache24/httpd.conf: Cannot load libexec/apache24/mod_auth_kerb.so into server: /usr/local/libexec/apache24/mod_auth_kerb.so: Undefined symbol "krb5_gss_register_acceptor_identity"

My OS version is:

10.2-RELEASE FreeBSD 10.2-RELEASE #0 r286666: Wed Aug 12 15:26:37 UTC 2015  root@releng1.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC  amd64

I built www/mod_auth_kerb2 from source using the default options. I also tried building with the "Use MIT implementation of GSS API" option but that didn't help. I fully updated my installed ports, and manually rebuild apache24, but that didn't help either.

Some online searching revealed that this is a known issue in FreeBSD 8.x and 9.x, but implied that it doesn't affect 10.x:

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=198645

I had a look at my /usr/bin/krb5-config and discovered that it already contains a change similar to the one in the patch mentioned in the above bug report:

lib_flags="$lib_flags -lgssapi -lgssapi_krb5 -lheimntlm"

(Mine has -lgssapi_krb5, and the patch has -lkrb5_gssapi)

Has anyone else encountered this issue? Any help would be appreciated.