LibNativeBridge: Add early init & env setup

Add a method to set up /proc/cpuinfo with enough privileges. Set
up the environment for an app in InitializeNativeBridge().

Turn on -Wall for libnativebridge.

Change-Id: I0b93da93251c6b4638de786bf98cf99df07c3fc2
Merge "LibNativeBridge: Add early init & env setup"
LibNativeHelper: No bind mount on mac

Cannot bind-mount /proc/cpuinfo on the mac.

Change-Id: Id5f0cd46ba0eba484477c56bbecf14d95e88d6f2
Merge "LibNativeHelper: No bind mount on mac"
LibNativeBridge: Fix mac build warning

Change-Id: I5a819cb5edb064b8a7288b5f2b3100c515421adf
Merge "LibNativeBridge: Fix mac build warning"