more clever 'unknown option'

src/sdl-instead/main.c

@@ -77,7 +77,7 @@ int main(int argc, char **argv)
 				encode_output = "lua.enc";
 		} else if (!strcmp(argv[i], "-version")) {
 			version_sw = 1;
-		} else {
+		} else if (argv[i][0] == '-') {
 			fprintf(stderr,"Unknow option: %s\n", argv[i]);
 			exit(1);
 		}