Switch to xz tarball

Signed-off-by: Daniel Engberg <daniel.engberg.lists@pyret.net>

Reported by buildbots (shortened and line-wrapped):
...
ln -sf -r .../ipkg-ramips_24kec/automake/usr/bin/automake-1.15
   .../ipkg-ramips_24kec/automake/usr/bin/automake
ln: invalid option -- 'r'

Signed-off-by: Michael Heimpold <mhei@heimpold.de>

To make automake work correctly it is necessary to have files
* automake
* aclocal
* automake-$(PKG_VERSION)
* aclocal-$(PKG_VERSION)

The files without version number can be supplied as symbolic
links.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

Automake is a tool for automatically generating Makefile.in files compliant
with the GNU Coding Standards.

A new package automake is provided.

version 2:
	do not reference staging directory in distributed files
	copy only one version of automake
	resolve whitespace issues

CC: Michael Heimpold <mhei@heimpold.de>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>