title: Using native Android system libraries outside NDK's stable API
body: <p>I was wondering if it's possible to use in native code the libraries of the Android system that are not directly exposed as an API from NDK.
  In particular how to include them in my native app code so that they can be linked with it.
  I know that it is discouraged, but the compatibility of my project across different Android releases is not a concern.</p>
  
  <p>What I'm trying to achieve is to skip some of the services that Android provides and try to sit closer to the kernel.
  Thanks.</p>