scripts/functions: introduce target_bits_32 and target_bits_64 variables

These variables behave the same for bitness as their counterparts do
for endianness: they are defined to the appropriate bitness.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Cody P Schafer <dev@codyps.com>

#!/bin/sh

set -e

printf "Running autoconf...\n"

autoconf -Wall --force

printf "Done. You may now run:\n    ./configure\n"