Add platform versions of the protobuf libraries.
Add platform versions of the protobuf libraries.

NDK libraries should not be linked in to platform code, so create a
separate version for the platform that is linked against libc++
instead of the NDK STLs.

Bug: 15193147
Change-Id: I3935e5dd3bd99676772a4b9681e275ef3601b855

MonkeyZZZZ/platform_external_protobuf,geekboxzone/mmallow_external_protobuf,geekboxzone/mmallow_external_protobuf,MonkeyZZZZ/platform_external_protobuf,geekboxzone/mmallow_external_protobuf,MonkeyZZZZ/platform_external_protobuf,geekboxzone/mmallow_external_protobuf,geekboxzone/mmallow_external_protobuf,MonkeyZZZZ/platform_external_protobuf,MonkeyZZZZ/platform_external_protobuf