Document Windows Cuda discovery in README

Author: AndrewGaspar

README.md

@@ -7,5 +7,10 @@ cuda-sys
 
 Rust binding to CUDA Driver(`libcuda.so`)/Runtime(`libcudart.so`) APIs
 
-- This crate does not include CUDA itself. You need to install on your own.
-- `$CUDA_LIBRARY_PATH` (e.g. `/opt/cuda/lib64`) will be used for `cargo:rustc-link-search`
+This crate does not include CUDA itself. You need to install on your own.
+
+`$CUDA_LIBRARY_PATH` (e.g. `/opt/cuda/lib64`) will be used for
+`cargo:rustc-link-search`. `$CUDA_LIBRARY_PATH` is not required on Windows when
+Cuda is installed via the typical Windows installer. To verify that cuda-sys can
+find your Cuda installation, you can check that the `CUDA_PATH` environment
+variable has been set.