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see https://forum.pjrc.com/threads/33450-Eclipse-ide-teensy3-2
If you install the eclipse ide you will find a bunch of files that are required and loaded including the Joystick class file that has...

Still investiagting, but so far i can tell you joystick is a class that need to be included, and its not the only one.
In the arduino ide this done for you and u dobt see. I am also still figuring...