scripts: munge .config to handle array variables

Transfrom array variables from pure strings (in the kconfig output)
into proper bash arrays declarations, for feeding to the build scripts.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
Signed-off-by: "Benoît THÉBAUDEAU" <benoit.thebaudeau@advansee.com>

 #!/bin/sh

 call_to=@@DEFAULT_LD@@

 case "${CTNG_LD_IS}" in

     bfd)    call_to=bfd;;

     gold)   call_to=gold;;

 esac

 exec "${0}.${call_to}" "$@"

 exit $?