Hennadii Stepanov

Also see https://github.com/google/leveldb/pull/1149.

> ... the CI environment is different from Launchpad's build environments... In what way?

Rebased.

Rebased.

> > While this approach introduces some duplication at present, it will ultimately enable us to consolidate how the IWYU tool is executed, allowing for a choice between using the...

Rebased. All feedback from @maflcko and @fanquake has been addressed. The IWYU-related workarounds are now documented with references to the relevant upstream issues.

Rebased. @maflcko Thank you for the review! Your feedback has been addressed.

> may be good to fix the aarch64 ci. Fixed.

Rebased to resolve a conflict with the merged #33116.

Rebased and addressed @maflcko's [comment](https://github.com/bitcoin/bitcoin/pull/31308#discussion_r2313401875).