RHEL 5-era autoconf did not define these, so define them manually
when they are missing.

Define builddir as '.'  The scripts require this.  It won't work
in the srcdir != builddir case, but we don't care about that for
RHEL 5.

This commit also moves the builddir / abs_srcdir variable setting
above the include of subdir-rules.mk, in case that include uses
these variables.

Useful script:

  for f in $(find -name Makefile.am | xargs fgrep '$(abs_srcdir)' -l) ; do
    if ! grep -q '^abs_srcdir' $f; then
      echo missing in $f
    fi
  done

Bind the easy parts of the 'btrfs' program.

The new APIs are:

btrfs-device-add: add devices to a btrfs filesystem
btrfs-device-delete: remove devices from a btrfs filesystem
btrfs-filesystem-sync: sync a btrfs filesystem
btrfs-filesystem-balance: balance a btrfs filesystem
btrfs-subvolume-create: create a btrfs snapshot
btrfs-subvolume-delete: delete a btrfs snapshot
btrfs-subvolume-list: list btrfs snapshots and subvolumes
btrfs-subvolume-set-default: set default btrfs subvolume
btrfs-subvolume-snapshot: create a writable btrfs snapshot

javah from old GNU classpath won't overwrite the target *.h file,
instead leaving the old one which results in a predictable build
failure.  Delete the target so this won't happen.

This returns information about the underlying devices of an MD
(software RAID) device.

Get ISO primary volume descriptor information for either ISO devices
or ISO files.