[PATCH][UPDATED] support for xz compression format

[Szymon Janc]

Hello,

New version of xz compression patch.
Changes since then:
- it works now :-)
- decoder dictionary can be enlarge up to DICT_BIT_SIZE defined in xz_lzma2.h
 (currently set to 30 = 128MiB)
- xz uses crc32 from libgcrypt-grub, internal crc implementation removed
- removed linux kernel related code from xz
- get rid of some not needed memcpy() calls
- xzio.mod stuff made according to Vladimir's comments
- simplified wraper (only 1 file - xz_wrap.h)
- number of other improvments and tons of bugfixes
- files licence changed from public domain to gpl3+

This patch also changes gnulib-wrap.h true/false definitions to make them truly
constants.

TODO and other questions:
- lack of file seek support, if files is compressed with small block size, it 
is 
  possible to implement pseudo-random access
- what is optimal i/o buffer size? like BUFSIZ macro in glibc
- default dictionary size should be chosen for files compression
- still need to do performance tests
- introduce some common layer for xzio/gzio etc ?

Comments are welcome

-- 
Szymon K. Janc
address@hidden // GG: 1383435

xz.diff.gz
Description: GNU Zip compressed data