[compiler-rt] [compiler-rt][fuzzer] SetThreadName build fix for Mingwin attempt (PR #106902)

[via llvm-commits]

Zentrik wrote:

I suspect it would, let me test it though. My concern with this approach was that mingw does not necessarily use pthreads. There seems to have been some discussion of that in https://github.com/llvm/llvm-project/pull/74981#issuecomment-1849982934

https://github.com/llvm/llvm-project/pull/106902