Need to compile a new libmbed.a file for Portenta_H7

I need to make some changes to the mbed_app.json filer that require a complete recompile.

Is there any way to recompile the GitHub - arduino/ArduinoCore-mbed

I basically just need to add a few lines in the mbed_app.json file here

and then recompile. I have not been able to recompile in windows, either using the mbed-os-to-arduino shell command in native windows, within the mbed studio, or in a linux shell in windows.

Any pointers on how to go about this. (I have asked this in the Mbed OS forum as well - not sure where is better)