[PATCH] D35377: [CMAKE] PR33717 When LLVM_APPEND_VC_REV = OFF, only create VCSRevision.h if it doesn't already exist.

[don hinton via Phabricator via llvm-commits]

hintonda added a comment.

> Could we also make some bot to check that "cmake/ninja" has nothing to do on incremental build without sync?

If you create a new bot, you'll get the new default value and get the pre r306858.

This change does 2 things:

- obviate unnecessary work when rerunning cmake if LLVM_APPEND_VC_REV=OFF (which was the previous default and probably still in your CMakeCache if your build directory was setup prior to r306858)
- allows users to toggle LLVM_APPEND_VC_REV and get correct behavior without needing to run git pull, etc...




https://reviews.llvm.org/D35377