[clang] [CUDA/HIP] Externalize __device__ const variables for symbol lookup (PR #177292)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> When we compile on the device side we pass `-fvisibility=hidden`, right? Is the symbol still visible for the lookup in this case?

I think the device attributes override default visibility, they show up as protected in the example code I gave.

https://github.com/llvm/llvm-project/pull/177292