kconfig/lxdialog: Make main() return 0

Fixes build with newer host toolchain.

Change-Id: I5c69bcdf6422d86b852e29768ba6dfbe0e9c2a76

Author: luk1337

scripts/kconfig/lxdialog/check-lxdialog.sh

@@ -47,7 +47,7 @@ trap "rm -f $tmp" 0 1 2 3 15
 check() {
         $cc -x c - -o $tmp 2>/dev/null <<'EOF'
 #include CURSES_LOC
-main() {}
+int main() { return 0; }
 EOF
 	if [ $? != 0 ]; then
 	    echo " *** Unable to find the ncurses libraries or the"       1>&2