README.android

This fork of Android differs in the following ways:
 - README.android
 - All Android.mk and Android.bp files
 - ALL MODULE_LICENSE_* files
 - libselinux/include/selinux/android.h
 - libselinux/src/android/android.c

All other changes should be upstreamed to selinux as
Android no longer carries changes outside of those files.

The upstream project can be found at:
https://github.com/SELinuxProject/selinux

Thus, since all changes are in separate files, updates merged from
upstream should occur with no merge conflicts.

This fork differs from upstream libselinux in at least the following ways:

* The Android fork omits compiling many of the src files and specifies
  custom build configurations. The exact details, are encoded in the
  Android.bp and Android.mk files.

* The SELinux policy files are all located in / rather than under
  /etc/selinux since /etc is not available in Android until /system
  is mounted and use fixed paths, not dependent on /etc/selinux/config.

* The kernel policy file (sepolicy in Android, policy.N in Linux) does
  not include a version suffix since Android does not need to support
  booting multiple kernels.

* The policy loading logic does not support automatic downgrading of
  the kernel policy file to a version known to the kernel, since this
  requires libsepol on the device and is only needed to support mixing
  and matching kernels and userspace easily.

* restorecon functionality, including recursive restorecon, has been
  been upstreamed as selinux_restorecon(), but there are residual
  differences between it and selinux_android_restorecon().

* Support for seapp_contexts, a new Android-specific SELinux
  configuration file has been added within android.c.