I'm trying to change something in android.webkit files in the android platform framework, and then use
mmm frameworks/base
to build this into the framework.jar file.
How do I build the system.img file so that this jar file gets linked? Also, without having to build the whole system.
As you note above you can make snod to just make the system image without dependencies.
You can make out/target/product/your-device/system.img which I believe will build a system image plus its dependencies, but nothing else.
Just make probably won't do what you want, because the Android build system will build everything, even stuff which isn't a dependency - it builds all the other packages just in case they are broken by changes to the APIs.