Sample Qt application
use pam to authenticate root.

(c) 2012 Waitman Gobble <waitman@waitman.net>
See License in source.

this allows you setuid your Qt app to allow a non-root user to run it as root,
but require the user to authenticate as root to run. In order to authenticate 
root using pam, the app must be setuid root 

(for example see "su")

$ ls -l /usr/bin/su
 -r-sr-xr-x  1 root  wheel  17304 Jun 10 17:10 /usr/bin/su


 1) chmod 4755 app_name
 2) chown root:wheel app_name
 
This example has two buttons, 'Authenticate', and 'Touch Test'. If the user
authenticates as root, the 'Touch Test' button will touch a file in /root.

Built on FreeBSD 10.0-CURRENT but should work on other versions of FreeBSD,
and may or may not work on other systems which use pam.

Ref:

/usr/include/security/pam.h
http://www.freebsd.org/doc/handbook/permissions.html
http://www.freebsd.org/doc/en_US.ISO8859-1/articles/pam/pam-sample-conv.html