[clang] [clang][CUDA] Define _NV_RSQRT_SPECIFIER for glibc-2.42/cuda-13.2 compatibility (PR #185701)

[Artem Belevich via cfe-commits]

Artem-B wrote:

Great. For some reason we can't include features.h somewhere on z390:

```
  # executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/clang -target s390x-ibm-zos -x cuda -fopenmp -c /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Headers/cuda_with_openmp.cu -o - --cuda-path=/home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Headers/../Driver/Inputs/CUDA/usr/local/cuda -nocudalib -isystem /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Headers/Inputs/include -isystem /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Headers/../../lib/Headers -fsyntax-only
  # .---command stderr------------
  # | clang: warning: argument unused during compilation: '-c' [-Wunused-command-line-argument]
  # | In file included from <built-in>:1:
  # | In file included from /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Headers/../../lib/Headers/__clang_cuda_runtime_wrapper.h:51:
  # | In file included from /usr/include/features.h:394:
  # | /usr/include/features-time64.h:20:10: fatal error: 'bits/wordsize.h' file not found
  # |    20 | #include <bits/wordsize.h>
  # |       |          ^~~~~~~~~~~~~~~~~
  # | 1 error generated when compiling for sm_52.
  # `-----------------------------
  # error: command failed with exit status: 1
```
@jhuber -- do you have any idea what's up with that? 

https://github.com/llvm/llvm-project/pull/185701