erofs-utils: get block device size correctly

fstat return block device's size of zero.
use ioctl to get block device's size.

Signed-off-by: shenmeng996 <shenmeng999@126.com>
[ Gao Xiang: check header files in configure.ac ]
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
2 files changed