[try removing c++ include from LLVM package]

Author: kinke

.github/workflows/supported_llvm_versions.yml

@@ -92,6 +92,7 @@ jobs:
           set -eux
           if [[ -d llvm ]]; then
             echo "Already cached"
+            rm -rf llvm/include/c++
             exit 0
           fi
 
@@ -109,6 +110,7 @@ jobs:
 
           # don't link lib{c++,unwind} libs from LLVM package, they'd need RPATH fiddling
           rm -f llvm/lib/lib{c++,unwind}.*
+          rm -rf llvm/include/c++
 
       - name: 'Linux: Make lld the default linker'
         if: runner.os == 'Linux'