Try to build fix

UI/GameScreen.cpp

@@ -56,10 +56,11 @@ GameScreen::~GameScreen() {
 	}
 }
 
-std::string int2hexstr(const int a) {
+const char* int2hexstr(const int a) {
 	std::stringstream stream;
 	stream << std::hex << a;
-	return stream.str();
+	auto s = stream.str();
+	return s.c_str();
 }
 
 void GameScreen::update() {

UI/GameScreen.h

@@ -29,7 +29,7 @@
 // Uses GameInfoCache heavily to implement the functionality.
 // Should possibly merge this with the PauseScreen.
 
-std::string int2hexstr(const int a);
+const char* int2hexstr(const int a);
 
 class GameScreen : public UIDialogScreenWithGameBackground {
 public: