We can just set M4 in the configure command instead of fixing up the paths
using sed afterwards. This makes the build more robust (and we're currently
preparing a change of the host staging dirs in LEDE that might break this
otherwise).

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

Switch to xz tarball

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

This patch provides package autoconf.

Autoconf is required to generated the configure script of autotools
projects.

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

[Fixed commit summary (first line of commit message)]

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