[PATCH] D83250: [clang] Enable errors for undefined TARGET_OS_ macros in Darwin driver

[Alex Lorenz via Phabricator via cfe-commits]

arphaman added a comment.

Please add a test-case as well.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D83250/new/

https://reviews.llvm.org/D83250