Merge "Preserve environment when launching overlay_remounter" into main am:...

        PLOG(FATAL) << "Failed to unlink " << or_dest;

    }

    const char* args[] = {or_dest.c_str(), nullptr};

    fexecve(dest.get(), const_cast<char**>(args), nullptr);

    fexecve(dest.get(), const_cast<char**>(args), environ);

    // execv() only returns if an error happened, in which case we

    // panic and never return from this function.