Using PlatformIO
PlatformIO is a development environment for microcontrollers.
First, make sure you have Visual Studio Code installed.
PlatformIO has an excellent setup guide which you can access here.
The jist of it though is you want to install the C/C++ extension:
then install the PlatformIO extension:
You'll see a little ant-head on the left toolbar. Click it and PlatformIO will start installing itself.
Restart visual studio when you see this message.
In Visual Studio Code, go to File -> Open Folder. Navigate to the platformio/ArduinoX86 subdirectory of the repo.
You'll next need to choose the correct environment for the board you have. Click the environment selector at the bottom of the window:
Warning
You must select an environment instead of using the default, even if you see your board is selected. Otherwise PlatformIO will attempt to build for both boards.
A panel will open at the top of the screen. Select giga_r1_m7 for Arduino Giga, or dueUSB for the DUE.
Click the little dropdown in the upper right corner of the window, and select Upload.
If you get DFU or other upload errors, make sure you can upload a sketch to your board in the Arduino IDE.