Build firewalld in Android.

* Drop firewalld/ prefix from #include paths.

* Rename the DBus interface definition to have a .dbus.xml suffix;
  needed for it to be picked up by the build infrastructure.

* Add __BRILLO__ preprocessor symbol for conditionally:

  1) Removing support for Permission Broker (currently not available and
     no concrete porting plan yet).

  2) Disable dropping privileges in minijail invocations (yet to be
     figured out).

  3) Adapting DBus bindings header paths (slightly different).

  4) Adapting helper utility paths (iptables, iproute2).

  5) Making punching of IPv6 firewall rules optional and autodetected.

* Re-license everything to AOSP and add NOTICE and
  MODULE_LICENSE_APACHE2.

* Added Android.mk for building all the targets we need, including
  init.firewalld.rc with proper SELinux attributes (when supported).

Bug: 22827985
Change-Id: I05f74f80f95f689b4bbf60a2708e76ef5495b96e
18 files changed