How to add a interface in /etc/config/network when I complie

I wan to compile firmware, I want to add a interface in /etc/config/network. What should I do to ?

Create a folder called 'files' in your buildroot. Add anything you want in this folder as if it were the root of your build image. Be aware that anything in this tree will overwrite existing files from the packages so you may want to edit an existing file first. In your example, add:

.../buildroot/files/etc/config/network

to provide a preconfigured network

Thans for your help.