I have installed the Phidgets libraries following the following link and the "Hello World" example was working. http://www.phidgets.com/docs/OS_-_Linux#Quick_Downloads

But when I install Phidgets ROS driver from https://github.com/ccny-ros-pkg/phidgets_drivers I got the error fatal error: libphidgets/phidget21.h: No such file or directory compilation terminated.

How does it happy? The libraries have been installed by the Linux driver, right?