reproduce (this is a W=1 build):
        git remote add hch-misc git://git.infradead.org/users/hch/misc.git
        git fetch --no-tags hch-misc xfs-data-crc
        git checkout 5b8b054ee57196ffbbd33ca472328041d4485762
        # 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 fs/xfs/