[clang] [Driver] Add LTO support for NetBSD (PR #187923)

[YAMAMOTO Takashi via cfe-commits]

yamt wrote:

> The expectation by setting `HasNativeLLVMSupport` is that the linker and other related tools are from LLVM.

looking at the users of the method, i thought it meant "linker can be lld". eg. with -fuse-ld=lld.

> Passing the parallelism flags comes from `tools::addLTOOptions()`.

can it disable thread creation?
i tried jobs=1 etc but no luck.



https://github.com/llvm/llvm-project/pull/187923