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

[Joseph Huber via cfe-commits]

jhuber6 wrote:

Honestly, no clue. Obviously including `features.h` can mean different things. I don't know the full semantics on different architectures.

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