opt: list ccan/typesafe_cb as a dependency.

ccan/opt/_info

@@ -58,6 +58,7 @@ int main(int argc, char *argv[])
 		return 1;
 
 	if (strcmp(argv[1], "depends") == 0) {
+		printf("ccan/typesafe_cb\n");
 		return 0;
 	}