player/lua: fix UB in integerness check

player/lua.c

@@ -655,8 +655,7 @@ static int script_set_property_bool(lua_State *L)
 
 static bool is_int(double d)
 {
-    int64_t v = d;
-    return d == (double)v;
+    return d >= (double)INT64_MIN && d <= (double)INT64_MAX && d == (int64_t)d;
 }
 
 static int script_set_property_number(lua_State *L)