xz multithreaded compression

$ dpkg -s liblzma5
Package: liblzma5
Status: install ok installed
(snip)
Version: 5.1.1alpha+20120614-2.1 

$ time `sudo cowbuilder --build fonts-horai-umefont_530-1.dsc`
real 1m8.378s
user 1m0.084s
sys 0m3.244s 

real 1m9.842s
user 1m0.964s
sys 0m3.856s 

real 1m9.355s
user 1m0.824s
sys 0m3.380s

xz 5.2 supports multithread, with local build (remove --disable-thread option in debian/rules)

$ dpkg -s liblzma5
Package: liblzma5
Status: install ok installed
(snip)
Version: 5.2.1-0.1 

real 1m7.946s
user 0m59.628s
sys 0m3.228s 

real 1m8.794s
user 1m0.072s
sys 0m3.556s 

real 1m7.580s
user 0m59.152s
sys 0m3.368s

Umm, not affected.

$ time `xz -T 0 fonts-horai-umefont_530.orig.tar`
real 0m15.488s
user 0m47.044s
sys 0m0.252s

$ time `xz -T 1 fonts-horai-umefont_530.orig.tar`
real 0m40.988s
user 0m40.804s
sys 0m0.124s

multithread itself is enabled.