kconfig/mconf: Initialize the default locale at startup

Fix bug where make menuconfig doesn't initialize the default locale, which
causes ncurses menu borders to be displayed incorrectly (lqqqqk) in
UTF-8 terminals that don't support VT100 ACS by default, such as PuTTY.

Signed-off-by: Jakub Horký <jakub.git@horky.net>
Link: https://patch.msgid.link/20251014154933.3990990-1-jakub.git@horky.net
[nathan: Alphabetize locale.h include]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Author: Jakub Horký

scripts/kconfig/mconf.c

@@ -12,6 +12,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <limits.h>
+#include <locale.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <string.h>
@@ -931,6 +932,8 @@ int main(int ac, char **av)
 
 	signal(SIGINT, sig_handler);
 
+	setlocale(LC_ALL, "");
+
 	if (ac > 1 && strcmp(av[1], "-s") == 0) {
 		silent = 1;
 		/* Silence conf_read() until the real callback is set up */