While running "make menuconfig" and "make mrproper"
some people experienced that /dev/null suddenly changed
permissions or suddenly became a regular file.
The main reason was that /dev/null was used as output
to gcc in the check-lxdialog.sh script and gcc did
some strange things with the output file; in this
case /dev/null when it errorred out.

Following patch implements a suggestion
from Bryan O'Sullivan <bos@serpentine.com> to
use gcc -print-file-name=libxxx.so.

Also the Makefile is adjusted to not resolve value of
HOST_EXTRACFLAGS and HOST_LOADLIBES until they are actually used.
This prevents us from calling gcc when running make *clean/mrproper

Thanks to Eyal Lebedinsky <eyal@eyal.emu.id.au> and
Jean Delvare <khali@linux-fr.org> for the first error reports.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
---

scripts/kconfig/lxdialog/check-lxdialog.sh uses gcc to check for
what libraries are present. Redirect output to /dev/null
so we do not generate an a.out.
Also included support for ncursesw - so if present prefer that
instead of ncurses.
The order is now (first is preferred):
1) ncursesw
2) ncurses
3) curses

The latter is to support SunOS.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

Cleaning up the lxdialog Makefile by factoring out the
ncurses compatibility checks.
This made the checks much more obvious and easier to extend.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

Remove support for lxdialog --checklist

The checklist lxdialog functionality is not used by menuconfig
(only the radiolist variant is used) and supporting it would
significantly complicate the forthcoming liblxdialog API.

Signed-off-by: Petr Baudis <pasky@suse.cz>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

The only lxdialog user i kconfig - for menuconfig.
So move it to reflect this.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>