The syntax is:
#AdditionalRes: <additional res folder> [, additional package]
It can be used multiple times.
The first parameter is the path to the additional res folder that will be added during compilation.
The second parameter is options. It is required when you wrap an Android library project which expects its own R.java file. The package parameter should be the same as the Android library project package.
The files are not copied to the normal res folder. They are packaged directly into the APK.