[compiler-rt] [llvm] [openmp] [Runtimes] Default build must use its own output dirs (PR #168266)

[Michael Kruse via llvm-commits]

Meinersbur wrote:

Post-land note: In a bootstrapping build, `PACKAGE_VERSION` is set by https://github.com/llvm/llvm-project/blob/main/llvm/cmake/modules/LLVMExternalProjectUtils.cmake#L404 which is why this "works".

IMHO this is a misuse of what `PACKAGE_VERSION` is intendend for. There should be an explicit switch telling the runtimes "use this directory as output ${PREFIX}" that defaults to ${CMAKE_BINARY_DIR}.

https://github.com/llvm/llvm-project/pull/168266