PAM authentication plugin shared libraries missing in binary packages

Trying to use the new PAM functionality MaxScale startup failed with:

var/log/maxscale/maxscale.log:2018-01-02 10:15:34 error : Unable to find library for module: PAMBackendAuth. Module dir: /usr/local/maxscale/lib/maxscale

Checking strace output it shows:

12994 access("/usr/local/maxscale/lib/maxscale/libPAMBackendAuth.so", F_OK) = -1 ENOENT (No such file or directory)

I checked the Ubuntu Xenial binary tarball, the .deb package and the CentOS7 RPM, neither seem to have the necessary plugin library files bundled