[PATCH] D125178: Warn if using `elifdef` & `elifndef` in not C2x & C++2b mode

[Ken Matsui via Phabricator via cfe-commits]

ken-matsui added a comment.

Thank you so much for your review!

My public email address is: `07softy_bride at icloud.com`.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D125178/new/

https://reviews.llvm.org/D125178