cmake LIBCXXABI_HAS_EXTERNAL_THREAD_API examples

Lewuathe/mlir-hello thirdparty/llvm-project/libcxxabi/CMakeLists.txt :64 

option(LIBCXXABI_HAS_EXTERNAL_THREAD_API
  "Build libc++abi with an externalized threading API.
  This option may only be set to ON when LIBCXXABI_ENABLE_THREADS=ON." OFF)

Lewuathe/mlir-hello thirdparty/llvm-project/libcxxabi/CMakeLists.txt :365 

message(FATAL_ERROR "LIBCXXABI_HAS_EXTERNAL_THREAD_API can only"
                        " be set to ON when LIBCXXABI_ENABLE_THREADS"
                        " is also set to ON.")

Lewuathe/mlir-hello thirdparty/llvm-project/libcxxabi/CMakeLists.txt :374 

message(FATAL_ERROR "The options LIBCXXABI_HAS_EXTERNAL_THREAD_API"
                        " and LIBCXXABI_HAS_PTHREAD_API cannot be both"
                        " set to ON at the same time.")

Lewuathe/mlir-hello thirdparty/llvm-project/libcxxabi/CMakeLists.txt :379 

message(FATAL_ERROR "The options LIBCXXABI_HAS_EXTERNAL_THREAD_API"
                        " and LIBCXXABI_HAS_WIN32_THREAD_API cannot be both"
                        " set to ON at the same time.")