gui2/tunit_attack: Fix non-deterministic crashes

t_string's implicit conversion to const std::string& returns a reference
to a(n aggregate class) field that gets destroyed as soon as the
t_string is, so binding this to a const reference does not extend the
referenced object's lifetime, resulting in a dangling reference and UB.

changelog

@@ -1,6 +1,9 @@
 Version 1.13.3+dev:
  * Language and i18n:
    * Updated translations:
+ * Miscellaneous and bug fixes:
+   * Fix non-deterministic crashes in the Attack Unit dialog resulting from
+     invalid memory references (regression introduced in 1.13.3).
 
 Version 1.13.3:
  * Greatly improved SDL 2 support. SDL 2 is now used by default build when

players_changelog

@@ -6,6 +6,10 @@ Version 1.13.3+dev:
  * Language and i18n:
    * Updated translations:
 
+ * Miscellaneous and bug fixes:
+   * Fix non-deterministic crashes in the Attack Unit dialog (regression
+     introduced in 1.13.3).
+
 Version 1.13.3:
  * SDL 2 is now used by default when building. This fixes the following bugs,
    among others:

src/gui/dialogs/unit_attack.cpp

@@ -200,8 +200,8 @@ static void set_weapon_info(twindow& window,
 		const SDL_Color d_cth_color =
 			int_to_color(game_config::red_to_green(defender.chance_to_hit));
 
-		const std::string& attw_name = !attacker_weapon.name().empty() ? attacker_weapon.name() : " ";
-		const std::string& defw_name = !defender_weapon.name().empty() ? defender_weapon.name() : " ";
+		const std::string attw_name = !attacker_weapon.name().empty() ? attacker_weapon.name() : " ";
+		const std::string defw_name = !defender_weapon.name().empty() ? defender_weapon.name() : " ";
 
 		std::string range = attacker_weapon.range().empty() ? defender_weapon.range() : attacker_weapon.range();
 		if (!range.empty()) {