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>

 # ia64 specific config options

 # depends on EXPERIMENTAL

 config ARCH_ia64

     select ARCH_SUPPORTS_64

     select ARCH_DEFAULT_64

     select ARCH_USE_MMU

     select ARCH_SUPPORTS_BOTH_ENDIAN

     help

       The ia64 architecture, as defined by:

         http://www.intel.com/design/itanium/arch_spec.htm