Build LLVM 16.0.3.

Author: elliottslaughter

.github/workflows/main.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       matrix:
         os: ['ubuntu-latest', 'macos-12', 'macos-14', 'windows-2022']
-        llvm: ['18.1.7']
+        llvm: ['16.0.3']
     steps:
       - uses: actions/checkout@v4
       - run: ./main.sh