Merge changes Ibeb2001a,I0440171a,I406674de,Ic7f2d12e,I6c0d71d7,Ibfcf1cde,I93cbe335,I6af69d67,Ic635afbb

* changes:
  ext4_utils: Fix warnings
  ext4_utils: Allow unknown block types in simg2img
  ext4_utils: Build simg2img for target
  ext4_utils: Convert simg2img from stdio to fds
  ext4_utils: Add ext2simg
  ext4_utils: Add an optional CRC chunk at the end of sparse files
  ext4_utils: Get rid of CRC in sparse file header
  ext4_utils: Add support for >2G input files
  ext4_utils: Move bg_desc_reserved_blocks from aux_info to info