This patch contains the changes to handle 64-bit block numbers stored in 
group descriptor structure.

Changes from the previous version:
- support of different group descriptor sizes for ext4 filesystems:
  -- Add new inline functions to get/set the block bitmap block, the 
inode bitmap block and the inode table block of a group.
  -- Add a new inline function to get the descriptor of a group.
- remove some'_EXT4FS_' conditional compilation and use instead 
INCOMPAT_64BIT tests.

  debugfs/debugfs.c         |   23 ++++----
  debugfs/logdump.c         |    4 -
  e2fsck/journal.c          |    4 +
  e2fsck/pass1.c            |   50 +++++++++--------
  e2fsck/pass1b.c           |   10 +--
  e2fsck/pass5.c            |   49 ++++++++---------
  e2fsck/super.c            |   35 ++++++------
  e2fsck/swapfs.c           |    4 -
  lib/ext2fs/alloc_stats.c  |   10 ++-
  lib/ext2fs/alloc_tables.c |   12 ++--
  lib/ext2fs/check_desc.c   |   12 ++--
  lib/ext2fs/closefs.c      |   18 ++++--
  lib/ext2fs/dblist.c       |    6 +-
  lib/ext2fs/ext2fs.h       |  132 
+++++++++++++++++++++++++++++++++++++++++++++-
  lib/ext2fs/imager.c       |    4 -
  lib/ext2fs/initialize.c   |    8 +-
  lib/ext2fs/inode.c        |   21 +++----
  lib/ext2fs/openfs.c       |   16 ++++-
  lib/ext2fs/rw_bitmaps.c   |   23 ++++----
  lib/ext2fs/swapfs.c       |    9 ++-
  lib/ext2fs/tst_iscan.c    |    2
  misc/dumpe2fs.c           |   30 +++++-----
  misc/e2image.c            |   12 ++--
  misc/mke2fs.c             |   21 ++++---
  misc/tune2fs.c            |    4 +
  resize/main.c             |    8 +-
  resize/online.c           |    6 +-
  resize/resize2fs.c        |   91 ++++++++++++++++++-------------
  28 files changed, 414 insertions(+), 210 deletions(-)