fix ncurses build error

copying.md

@@ -139,7 +139,8 @@ _the openage authors_ are:
 | Jens Nyman                  | nymanjens                   | nymanjens dawt nj à gmail dawt com                |
 | Deepak Dinesh               | deepak                      | d.deepakdinesh13 à gmail dawt com                 |
 | Damien Lejay                | dlejay                      | lejay à paracompact dawt space                    |
-| Talha Aamir                | sarcxd                      | sarcxd à gmail dawt com                    |
+| Talha Aamir                 | sarcxd                      | sarcxd à gmail dawt com                           |
+| Matthias Geiger             | CountOmega                  | matthias dawt geiger1024 à outlook dawt com       |
 
 If you're a first-time committer, add yourself to the above list. This is not
 just for legal reasons, but also to keep an overview of all those nicknames.

libopenage/event/demo/gui.cpp

@@ -1,4 +1,4 @@
-// Copyright 2016-2019 the openage authors. See copying.md for legal info.
+// Copyright 2016-2022 the openage authors. See copying.md for legal info.
 
 #include "gui.h"
 
@@ -133,7 +133,7 @@ void Gui::init() {
 	int row = (y - buffer.size()) / 2;;
 	int col = (x - colwidth) / 2;
 	for (const auto &c : buffer) {
-		mvprintw(row++, col, c);
+		mvprintw(row++, col, "%c", c);
 	}
 
 	attroff(COLOR_PAIR(COLOR_DEBUG));
@@ -206,7 +206,7 @@ void Gui::draw(const std::shared_ptr<PongState> &state, const curve::time_t &now
 	// show log
 	int msg_i = 0;
 	for (auto & msg : this->log_msgs) {
-		mvprintw((6 + msg_i), state->display_boundary[0]/2 + 10, msg.c_str());
+		mvprintw((6 + msg_i), state->display_boundary[0]/2 + 10, "%s", msg.c_str());
 		msg_i += 1;
 	}