build.rs was hardcoded for sm_90 (incorrectly labelled Ada Lovelace/RTX
5090). Fix for RTX 5060 Ti (sm_120, Blackwell):
- Auto-detect SM via CUDA_ARCH env var (default sm_120); compute_ prefix
derived automatically so compute_120/sm_120 are no longer hardcoded.
- nvcc resolution: try PATH first, then CUDA_PATH/bin/nvcc, CUDA_HOME,
and common installation prefixes — no longer panics when nvcc is at
/usr/local/cuda-13.1/bin but not in $PATH.
- PTX version: sm_100+ → .version 8.0 (PTX ISA 8.0 for Blackwell).
- No-GPU branch: remove the warning — CPU fallback is valid, there is
no reason to warn every build when cuda/metal are intentionally off.
Co-Authored-By: Claude Sonnet 4.6 <[email protected]>
