This patch adds the initial support for linking NVPTX offloading code
using the clang-linker-wrapper tool. This uses the extracted device
files and runs nvlink on them. Currently this is then passed to the
existing toolchain for creating linkable OpenMP offloading programs
using clang-offload-wrapper and compiling it manually using llc.
More work is required to support LTO, Bitcode linking, AMDGPU, and x86
offloading.
Depends on D116545