Take only the include dir from llvmPackages_9.llvm.dev

let

  # The LLVM 9 headers have a couple bugs we need to patch

  fixedLlvmDev = runCommand "llvm-dev-${llvmPackages_9.llvm.version}" { buildInputs = [git]; } ''

    cp -r ${llvmPackages_9.llvm.dev} $out

    mkdir $out

    cp -r ${llvmPackages_9.llvm.dev}/include $out

    cd $out

    chmod -R u+w include

    git apply ${./fix-llvm-include.patch}