[llvm] [Offload] Correctly regenerate API files if modified (PR #141679)

[Callum Fare via llvm-commits]

https://github.com/callumfare commented:

Thanks, one comment but otherwise it looks good.

At this point I'm not against removing the checked-in generated files to conform with the way Tablegen is used elsewhere, if that's something we'd prefer. The clang-format step could be optional in that case.

https://github.com/llvm/llvm-project/pull/141679