fixed VC issue with VC

include/squirrel.h

@@ -400,7 +400,7 @@ SQUIRREL_API void sq_setnativedebughook(HSQUIRRELVM v,SQDEBUGHOOK hook);
 #ifdef __GNUC__
 # define SQ_UNUSED_ARG(x) __attribute__((unused)) x
 #else
-# define SQ_UNUSED_ARG(x) 
+# define SQ_UNUSED_ARG(x) x
 #endif
 
 #ifdef __cplusplus