Update CMakeLists.txt

[compnerd]

Fix the unified build by using LLVM_CMAKE_PATH rather than LLVM_CMAKE_DIR. This matches the previous behaviour, and relies on the standalone build defining LLVM_CMAKE_PATH through LLVM_CMAKE_DIR.

[compnerd]

CC: @JDevlieghere @etcwilde

[compnerd]

@swift-ci please test

[JDevlieghere]

So this fixes the unified build (and works for the standalone build), but breaks llvm.org. Also, other projects are all using LLVM_CMAKE_DIR.

llvm/include/llvm/Support/CMakeLists.txt
6:set(generate_vcs_version_script "${LLVM_CMAKE_DIR}/GenerateVersionFromVCS.cmake")

lld/Common/CMakeLists.txt
11:set(generate_vcs_version_script "${LLVM_CMAKE_DIR}/GenerateVersionFromVCS.cmake")

clang/lib/Basic/CMakeLists.txt
11:set(generate_vcs_version_script "${LLVM_CMAKE_DIR}/GenerateVersionFromVCS.cmake")

In the unified build, can we set LLVM_CMAKE_DIR based on LLVM_CMAKE_PATH?

[compnerd]

We do the inverse in the standalone build: https://github.com/apple/llvm-project/blob/stable/20210726/lldb/cmake/modules/LLDBStandalone.cmake#L14

Where in the unified build were you thinking of changing that? The current unified build actually does not have a special path, it works the same as the upstream build. On the other hand, next does something weird: https://github.com/apple/llvm-project/blob/next/lldb/cmake/modules/LLDBStandalone.cmake#L14

Could this be a bad merge?