reproduce (this is a W=1 build):
        # https://github.com/brauner/linux/commit/1c10fd3362d56837a4f01ef8352f8fce1308bacc
        git remote add brauner-github https://github.com/brauner/linux.git
        git fetch --no-tags brauner-github work.mnt_idmap.statmount
        git checkout 1c10fd3362d56837a4f01ef8352f8fce1308bacc
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash samples/