Add support for Android's logging subsystem.

This patch adds support for Android's logging subsystem in Tor. When
debugging Android applications it is useful to be able to collect
information about the application running on the platform via the
various system services that is available on the platform.

This patch allows you to add "Log notice android" to your torrc and have
Tor send everything above and including the notice severity to Android's
ring buffer which can be inspected using the 'adb logcat' program.

See: XXX
1 job for ahf/android-logging in 48 minutes and 5 seconds (queued for 2 seconds)
Status Job ID Name Coverage
passed #39207793