reproduce (this is a W=1 build):
        # https://github.com/davidhildenbrand/linux/commit/0963570e536ad72776105fbd404b09e35b19927a
        git remote add davidhildenbrand https://github.com/davidhildenbrand/linux
        git fetch --no-tags davidhildenbrand folded_pgtable
        git checkout 0963570e536ad72776105fbd404b09e35b19927a
        # apt-get install llvm-dev

        # save the config file
        make W=1 ARCH=i386 olddefconfig
        make W=1 ARCH=i386 
        make W=1 headers_install
        make W=1 -C tools/testing/selftests