## Summary
`support.GetLibInfo` exposed ~30 build-time `TVM_INFO_*` strings (git
hash, LLVM/MLIR versions, every `USE_*` flag). Real callers reduce to
"is this feature enabled?" — better answered at runtime. `USE_CUDA=ON`
does not mean a CUDA device is loadable; runtime discovery is the actual
signal. Git versioning is already tracked via `tvm.__version__`.
Changes:
- Delete `src/support/libinfo.cc`, `cmake/modules/LibInfo.cmake`,
`tests/lint/check_cmake_options.py`, and the `check-cmake-options`
pre-commit hook.
- Delete `tvm.support.libinfo()` (no shim — callers migrate to runtime
discovery).
- Add `tvm.support.detect_active_modules()` which queries the FFI global
function registry for `ffi.Module.create.<kind>` registrations (cuda,
vulkan, opencl). `describe()` now prints active runtimes instead of
CMake build flags.
- Migrate 5 in-tree callers: `_get_targets()` uses `cudnn.exists()` /
`tvm.runtime.enabled()` for CUDNN and Hexagon; `_cmake_flag_enabled()`
is rewritten as a static map from cmake flag names to
`tvm.runtime.enabled()` or FFI-registry probes; `clml_sdk_version()`
uses the existing `relax.get_openclml_version` FFI global;
`test_clml_ops.py` uses the new helper.
After this PR: `src/support/` is header-only.
Tianqi Chen
58fc749f27