sccache didn't fuck anything up, finally

todo.md

@@ -24,6 +24,7 @@
 - The exact problematic arguments were confirmed with a direct `sccache clang ...` probe using the wrapper-emitted argv.
 - The new ccache-style `sccacheWrapper` / `sccacheStdenv` path evaluates successfully.
 - `intel-sycl.stdenv.cc` now also evaluates successfully with the ccache-style `sccache.links` replacement in place.
+- The custom kernel helper now normalizes config-only `kernelPatches` entries to `{ patch = null; ... }` before calling `buildLinux`, which fixes `devenv shell -- build` failing during kernel evaluation.
 
 ## Next Checks
 
@@ -33,6 +34,5 @@
 - For CMake packages, the practical fallback is to export `SCCACHE_WRAPPED_COMPILER_PASSTHROUGH=1` for the whole `configurePhase` and unset it in `postConfigure`; caching matters in `buildPhase`, not in compiler-ID probes.
 - Apply the shared CMake helper to stalled subpackages too, not just top-level wrappers. `oneapi-math-sycl-blas` is one such case.
 - The same helper may also be needed on the outer package if the subpackage is fixed but the wrapper package then stalls at its own CMake configure.
-- Build the patched `sccache` package.
 - Run a minimal hello-world derivation with the new `sccacheStdenv` and confirm repeated compiles produce cache hits.
 - If that works, switch current consumers to the ccache-style path and remove obsolete wrapper-patching logic.