Actualmente estoy tratando de construir android-5.1.0_r5. Revisé las fuentes y no hice modificaciones. Sin embargo, al compilar me sale el siguiente error.

Checking API: checkpublicapi-current
out/target/common/obj/PACKAGING/public_api.txt:20: error 5: Added public field android.Manifest.permission.BACKUP
out/target/common/obj/PACKAGING/public_api.txt:82: error 5: Added public field android.Manifest.permission.INVOKE_CARRIER_SETUP
out/target/common/obj/PACKAGING/public_api.txt:106: error 5: Added public field android.Manifest.permission.READ_PRIVILEGED_PHONE_STATE
out/target/common/obj/PACKAGING/public_api.txt:116: error 5: Added public field android.Manifest.permission.RECEIVE_EMERGENCY_BROADCAST

******************************
You have tried to change the API from what has been previously approved.

To make these errors go away, you have two choices:
   1) You can add "@hide" javadoc comments to the methods, etc. listed in the
      errors above.

   2) You can update current.txt by executing the following command:
         make update-api

      To submit the revised current.txt to the main Android repository,
      you will need approval.
******************************

Y diferenciar los archivos api txt públicos sí muestra una diferencia.

diff frameworks/base/api/current.txt out/target/common/obj/PACKAGING/public_api.txt 
19a20
>     field public static final java.lang.String BACKUP = "android.permission.BACKUP";
80a82
>     field public static final java.lang.String INVOKE_CARRIER_SETUP = "android.permission.INVOKE_CARRIER_SETUP";
103a106
>     field public static final java.lang.String READ_PRIVILEGED_PHONE_STATE = "android.permission.READ_PRIVILEGED_PHONE_STATE";
112a116
>     field public static final java.lang.String RECEIVE_EMERGENCY_BROADCAST = "android.permission.RECEIVE_EMERGENCY_BROADCAST";

Sin embargo, no puedo entender de dónde provienen esos campos públicos adicionales. ¿Algunas ideas?