[llvm] [llvm] Fix illumos header macro conflicts. (PR #177380)

[Nikita Popov via llvm-commits]

nikic wrote:

As it's not LLVM itself including that header, I think you should work around this in clickhouse. Preferably after filing an illumos issue to get this fixed.

https://github.com/llvm/llvm-project/pull/177380