I believe the current code is not modified with Arduino anymore. You can’t load it onto the copter or compile it with that IDE. Some of the old PDE’s where left in that version where the current version has all of them removed. Even the current Arduino ide is converting them to .ino extensions which are just cpp files.
I don’t know if the examples work as they were broke but I think they are fixed now.
The tool chain is needed to build the current code but you are building 3.2.1 which does not require some of the newer boards and functions. I have not compiled code back that far. Hopefully the development site will give you some insight.