Quick enabler for GPIO userspace access to any user.
Download "enable_gpio.c" and "make.sh" to any folder on your Linux Box ( I use it on the Raspberry Pi). Then type "sudo bash make.sh".
This will create the "enable_gpio" executable and save it in /usr/bin, and it will be made SETUID root. An entry in /etc/rc.local will be made to start it on every boot.
Now every user has access to /sys/class/gpio/export and unexport.
Why to use this? Because it is a pain to run programs as "root", just to have access to GPIO-Ports...