(svn r2994) Another small hack regarding currencies: add a #define to emulate a variable, that holds the current currency; again this should increase readability

currency.h

@@ -21,9 +21,9 @@ extern const StringID _currency_string_list[];
 
 // XXX small hack, but makes the rest of the code a bit nicer to read
 #define _custom_currency (_currency_specs[23])
+#define _currency ((const CurrencySpec*)&_currency_specs[_opt_ptr->currency])
 
 uint GetMaskOfAllowedCurrencies(void);
-uint GetCurrentCurrencyRate(void);
 void CheckSwitchToEuro(void);
 
 #endif /* CURRENCY_H */