[ffigen] Update README.md (#46)

pkgs/ffigen/README.md

diff --git a/pkgs/ffigen/README.md b/pkgs/ffigen/README.md
index 14053ce..ce829cf 100644
--- a/pkgs/ffigen/README.md
+++ b/pkgs/ffigen/README.md
@@ -46,7 +46,7 @@
 
 #### Windows
 1. Install Visual Studio with C++ development support.
-2. Install [LLVM](https://releases.llvm.org/download.html).
+2. Install [LLVM](https://releases.llvm.org/download.html) or `winget install -e --id LLVM.LLVM`.
 
 #### MacOS
 1. Install Xcode.