PAM auth has apparently stopped working in the latest nginx packages from backports. This was previously working with backports packages, and still works with the packages from the regular jessie repos.
Here's the config error:
root@test-git:/home/durist# nginx -t
nginx: [emerg] unknown directive "auth_pam" in /etc/nginx/nginx.conf:67
nginx: configuration file /etc/nginx/nginx.conf test failed
I have the following nginx packages installed:
ii libnginx-mod-http-auth-pam 1.10.2-4~bpo8+1 amd64 PAM authentication module for Nginx
ii libnginx-mod-http-dav-ext 1.10.2-4~bpo8+1 amd64 WebDAV missing commands support for Nginx
ii libnginx-mod-http-echo 1.10.2-4~bpo8+1 amd64 Bring echo and more shell style goodies to Nginx
ii libnginx-mod-http-geoip 1.10.2-4~bpo8+1 amd64 GeoIP HTTP module for Nginx
ii libnginx-mod-http-image-filter 1.10.2-4~bpo8+1 amd64 HTTP image filter module for Nginx
ii libnginx-mod-http-subs-filter 1.10.2-4~bpo8+1 amd64 Substitution filter module for Nginx
ii libnginx-mod-http-upstream-fair 1.10.2-4~bpo8+1 amd64 Nginx Upstream Fair Proxy Load Balancer
ii libnginx-mod-http-xslt-filter 1.10.2-4~bpo8+1 amd64 XSLT Transformation module for Nginx
ii libnginx-mod-mail 1.10.2-4~bpo8+1 amd64 Mail module for Nginx
ii libnginx-mod-stream 1.10.2-4~bpo8+1 amd64 Stream module for Nginx
ii nginx-common 1.10.2-4~bpo8+1 all small, powerful, scalable web/proxy server - common files
iF nginx-full 1.10.2-4~bpo8+1 amd64 nginx web/proxy server (standard version)