resolve demo-debian-bullseye cxx11 abi string issue

Somewhere in the toolchain there's a flag missing resulting in:

```
client.cc:(.text+0x27fe): undefined reference to `google::cloud::v2_34::Project::Project(std::__cxx11::basic_string, std::allocator >)'

```

首先在 demo-debian-bullseye 环境中重现链接器错误，并检查 toolchain 和构建配置以查找缺失的 ABI 设置。当 demo 成功链接且不再出现 undefined reference to the C++11 ABI string constructor 时，即表示完成。

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