libupnp: requires threads

Fixes:
http://autobuild.buildroot.net/results/ac5a18a6241d36a751cce1867c4da63047eafbaa/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
busybox: 1.21.1 fix for move_to_unaligned16()

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
busybox: add 1.21.0 xz fix

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
busybox: 1.21.0 platform fix-on-fix

The unxz hunk was missing.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>