[compiler-rt] [sanitizer_common] Updated build fix for newer NetBSD (PR #134742)

[Brad Smith via llvm-commits]

brad0 wrote:

> what was the issue with the previous commit ?

Sorry, took a bit to get a -current VM up and running to check myself. Looks like the previous patch fixed -current but broke 10.

-current builds this chunk of code but 10 with the previous patch failed like so..

```
sanitizer_linux_libcdep.cpp:521:27: error: use of undeclared identifier '__lwp_getprivate_fast'; did you mean '_lwp_getprivate'?
```

https://github.com/llvm/llvm-project/pull/134742