diff --git a/src/currency.h b/src/currency.h
--- a/src/currency.h
+++ b/src/currency.h
@@ -37,7 +37,7 @@ struct CurrencySpec {
 
 extern CurrencySpec _currency_specs[NUM_CURRENCY];
 
-// XXX small hack, but makes the rest of the code a bit nicer to read
+/* XXX small hack, but makes the rest of the code a bit nicer to read */
 #define _custom_currency (_currency_specs[CUSTOM_CURRENCY_ID])
 #define _currency ((const CurrencySpec*)&_currency_specs[_game_mode == GM_MENU ? _settings_newgame.locale.currency : _settings_game.locale.currency])