Stop using libstdc++.
Stop using libstdc++.

Statically link libc++ because we copy aprotoc to unbundled projects
where libc++.so may not be available.

Change-Id: I1f1abc015696c1ccd8600338c147d51aca2253a1

MonkeyZZZZ/platform_external_protobuf,MonkeyZZZZ/platform_external_protobuf,MonkeyZZZZ/platform_external_protobuf,MonkeyZZZZ/platform_external_protobuf,MonkeyZZZZ/platform_external_protobuf