title: Reading Android.mk files in sub-dirs recursively
body: <p>I would just like to ask what should be written in the Android.mk file to also call the mk files in the sub-directories of the current directory. 
  <br><br>
  Example:<br>
  /packages/Android.mk<br>
  /package/groupA/Android.mk<br>
  /packages/groupA/AppA/Android.mk<br>
  /packages/groupA/AppB/Android.mk<br></p>
  
  <p>I know that by using <code>include $(call all-subdir-makefiles)</code>, the Android.mk file in the immediate sub-directory will be read (example: /package/groupA/Android.mk). However, /packages/groupA/AppA/Android.mk and /packages/groupA/AppB/Android.mk will not be read. </p>
  
  <p>I wonder if there is other macro that do the recursive reading of the Android.mk for all sub-directories.</p>
  
  <p>Thanks,<br>
  artsylar</p>