[llvm] [llvm][Support] Add support for thread naming for Haiku (PR #107646)

[Brad Smith via llvm-commits]

brad0 wrote:

Should be filling in get_max_thread_name_length_impl(). I'd add it below OpenBSD and it looks like you could return B_OS_NAME_LENGTH.

https://github.com/llvm/llvm-project/pull/107646