c-ares searching for gethostbyname in the libnsl library, however in the
version that shipped with gRPC it doing it wrong [1], since it uses
CHECK_LIBRARY_EXISTS(), which will return TRUE even if the function exists in
another dependent library. The upstream already contains correct macro [2],
but it is not included in gRPC (even upstream gRPC, not the one that is
shipped with clickhousee).
[1]: e982924ace/CMakeLists.txt (L125)
[2]: 44fbc81368/CMakeLists.txt (L146)
And because if you by some reason have libnsl [3] installed, clickhouse will
reject to start w/o it. While this is completelly different library.
[3]: https://packages.debian.org/bullseye/libnsl2
