diff -r b6bf20def07f -r a52574521bea configure
--- a/configure	Sun Aug 14 16:06:20 2011 +0200
+++ b/configure	Thu Aug 18 16:05:48 2011 +0200
@@ -453,6 +453,9 @@
 has_or_abort prog=tar
 has_or_abort prog=gzip
 has_or_abort prog=bzip2
+has_or_warn  prog=xz                                        \
+             kconfig=has_xzutils                            \
+             err="xz-comoressed tarballs will not be used"
 has_or_abort prog=readlink
 has_or_abort prog=objcopy var=objcopy
 has_or_abort prog=objdump var=objdump