kconfig: resync curses check with Linux kernel

check-lxdialog.sh breaks on 64-bit distributions which are lacking
the lib -> lib64 symlinks (eg. some Fedora).

The script from the 2.6.35 Linux kernel is reportedly functional
on the systems that were requiring the current hack. See:
http://sourceware.org/ml/crossgcc/2010-09/msg00113.html

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 COPYING