[libclc] [libclc] Fix using normalized triple for the directory name (PR #194607)

[Konrad Kleine via cfe-commits]

kwk wrote:

I've finished packaging libclc with the SPIRV backend in our monolithic build of LLVM and the resulting `libclc-spirv` and `libclc` RPMs now contain the following files. I'm pretty happy with the `spirv-mesa-mesa3d` part TBH. If you want to see the build log for all cmake settings, feel free to check it out [here](https://download.copr.fedorainfracloud.org/results/@fedora-llvm-team/llvm-snapshots-libclc/fedora-rawhide-x86_64/10430046-llvm/builder-live.log.gz).

```console
$ rpm -ql libclc-spirv
/usr/lib/clang/23/lib/spirv-mesa-mesa3d/libclc.spv
/usr/lib/clang/23/lib/spirv64-mesa-mesa3d/libclc.spv
/usr/share/doc/libclc-spirv
/usr/share/doc/libclc-spirv/CREDITS.TXT
/usr/share/doc/libclc-spirv/README.md
/usr/share/licenses/libclc-spirv
/usr/share/licenses/libclc-spirv/LICENSE.TXT
```

```console
rpm -ql libclc
/usr/lib/clang/23/lib/amdgcn-amd-amdhsa/libclc.bc
/usr/lib/clang/23/lib/clspv-unknown-unknown/libclc.bc
/usr/lib/clang/23/lib/clspv64-unknown-unknown/libclc.bc
/usr/lib/clang/23/lib/nvptx64-nvidia-cuda/libclc.bc
/usr/share/doc/libclc
/usr/share/doc/libclc/CREDITS.TXT
/usr/share/doc/libclc/README.md
/usr/share/licenses/libclc
/usr/share/licenses/libclc/LICENSE.TXT
```

> What we should do is make the canonical triple for your target `spirv64-unknown-vulkan` and then change clang to add a `__VULKAN__` macro like how people already handle `__WIN32` or `__LINUX__`. I'll look into that

IMHO, if this PR could get merged, this would be a step in the right direction. Changing the clspv triple can be done in a separate PR, no?


https://github.com/llvm/llvm-project/pull/194607