[clang] [clang] Fix wrong warning about missing init for flexible array members (PR #66341)

[Mariya Podchishchaeva via cfe-commits]

Fznamznon wrote:

> (double checking: this does not need a release note because it fixes something that was changed post 17 branch. Correct?)

Exactly. There is a release note for guilty change.

https://github.com/llvm/llvm-project/pull/66341