build(flake): add workaround for enabling CUDA on non-NixOS systems

Bibliography:
- https://discourse.nixos.org/t/on-nixpkgs-and-the-ai-follow-up-to-2023-nix-developer-dialogues/37087
- https://nixos.org/community/teams/cuda
  - https://github.com/orgs/NixOS/projects/27
- https://alternativebit.fr/posts/nixos/nix-opengl-and-ubuntu-integration-nightmare
  - https://lobste.rs/s/7h20zl/nix_opengl_ubuntu_integration_nightmare
- NixOS/nixpkgs#11390 (comment)
  - NixOS/nixpkgs#269475
- tweag/nix-hour#61

flake.nix

@@ -32,8 +32,14 @@
         postShellHook = ''
         '';
 
-        # Enable python libraries to discover libstdc++.so.6
-        LD_LIBRARY_PATH = with pkgs; lib.makeLibraryPath [ stdenv.cc.cc ];
+        LD_LIBRARY_PATH = with pkgs; lib.makeLibraryPath [
+          # Enable python libraries to discover libstdc++.so.6
+          stdenv.cc.cc
+
+          # FIXME: workaround for finding libcuda.so on non-NixOS systems
+          "/usr"  # General location
+          "/usr/lib/wsl"  # On WSL
+        ];
       };
     });
 }