cuda no longer supported on mac os

Author: brettkoonce

Installation.md

@@ -202,12 +202,6 @@ the meantime, you may be able to run Ubuntu 18.04 toolchains on Ubuntu 20.04 usi
     $ export PATH=/Library/Developer/Toolchains/swift-latest/usr/bin:"${PATH}"
     ```
 
-7. **CUDA-only**: If you downloaded a CUDA GPU-enabled toolchain, add the library path(s) for CUDA and cuDNN to `$LD_LIBRARY_PATH`:
-
-    ```console
-    $ export LD_LIBRARY_PATH=/usr/local/cuda/lib:"${LD_LIBRARY_PATH}"
-    ```
-
 ## Linux
 
 Packages for Linux are tar archives including a copy of the Swift compiler, lldb, and related tools. You can install them anywhere as long as the extracted tools are in your PATH.