[clang] [Clang] Add missing macro undefs in AttributeSpellingList emitter (PR #141090)

[Kazu Hirata via cfe-commits]

https://github.com/kazutakahirata approved this pull request.

LGTM.  I've verified that the warning goes away.  Thank for fixing this quickly!

https://github.com/llvm/llvm-project/pull/141090