package/mc: fix build with ncurses

wchar support in ncurses is needed since version 4.8.26 and
8b4386df83

Fixes:
 - http://autobuild.buildroot.org/results/446eb0a15a728e2fe7a58312bb7329983b2df647

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/mc/0001-Ticket-4181-FTBFS-against-NCurses-on-OS-X-10-9-5.patch

@@ -0,0 +1,32 @@
+From ba62dd32add2767d6d13f9abb82f43304418740f Mon Sep 17 00:00:00 2001
+From: Andrew Borodin <aborodin@vmail.ru>
+Date: Sun, 24 Jan 2021 14:19:22 +0300
+Subject: [PATCH] Ticket #4181: FTBFS against NCurses on OS X 10.9.5.
+
+lib/tty/tty-ncurses.h: define _XOPEN_SOURCE_EXTENDED to use cchar_t,
+getcchar(), setcchar().
+
+Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
+[Retrieved from:
+https://github.com/MidnightCommander/mc/commit/ba62dd32add2767d6d13f9abb82f43304418740f]
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ lib/tty/tty-ncurses.h | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/lib/tty/tty-ncurses.h b/lib/tty/tty-ncurses.h
+index 9962c7c413..d75df9533a 100644
+--- a/lib/tty/tty-ncurses.h
++++ b/lib/tty/tty-ncurses.h
+@@ -2,6 +2,11 @@
+ #ifndef MC__TTY_NCURSES_H
+ #define MC__TTY_NCURSES_H
+ 
++/* for cchar_t, getcchar(), setcchar() */
++#ifndef _XOPEN_SOURCE_EXTENDED
++#define _XOPEN_SOURCE_EXTENDED
++#endif
++
+ #ifdef USE_NCURSES
+ #ifdef HAVE_NCURSES_CURSES_H
+ #include <ncurses/curses.h>

package/mc/Config.in

@@ -6,6 +6,7 @@ config BR2_PACKAGE_MC
 	select BR2_PACKAGE_LIBGLIB2
 	# mc prefers slang, but can use ncurses too
 	select BR2_PACKAGE_SLANG if !BR2_PACKAGE_NCURSES
+	select BR2_PACKAGE_NCURSES_WCHAR if BR2_PACKAGE_NCURSES
 	help
 	  GNU Midnight Commander is a visual file manager, licensed
 	  under GNU General Public License. It can use either SLang