#959 ./setup.sh fails on Gentoo Linux

Description

The default `./setup.sh` approach fails on Gentoo Linux (profile: `default/linux/amd64/23.0/desktop/gnome/systemd`), no matter how you specify, export or even symlink `CUDA_PATH`, `CUDACXX` or `LD_LIBRARY_PATH`.

The only way to truly build Strata is:

`./setup.sh`
let it fail
`rm -rf build`
```
   /usr/bin/cmake -G Ninja \
  -DCMAKE_MAKE_PROGRAM=/usr/bin/ninja \
  -S . -B build \
  -DCMAKE_BUILD_TYPE=Release \
  -DSTRATA_ENABLE_CUDA=ON \
  -DSTRATA_BUILD_TESTS=OFF \
  -DCMAKE_CUDA_ARCHITECTURES=86 \
  -DCMAKE_CUDA_COMPILER=/opt/cuda/bin/nvcc \
  -DSTRATA_GGML_DIR=./third_party/llama.cpp
```
`ninja -C build`
`./setup.sh`

tl;dr, Gentoo by default installs CUDA in `/opt/cuda/` and may not properly propagate `LD_LIBRARY_PATH`.
Setup scripts in Strata should be aware of this.