companion_tools/autoconf: add autoconf tool

Initial version of adding autoconf as a companion tool.

Signed-off-by: Richard Strand <richard.strand@icomera.com>
[yann.morin.1998@anciens.enib.fr: use generic overide tools dir]
[yann.morin.1998@anciens.enib.fr: update menu entries]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 reporter_name="Nye Liu"

 reporter_url="http://sourceware.org/ml/crossgcc/2008-10/msg00046.html"

 reporter_comment=""