+int wait_for_terminate_and_warn(const char *name, pid_t pid);
+
+_noreturn_ void freeze(void);
+
+bool null_or_empty(struct stat *st);
+
+DIR *xopendirat(int dirfd, const char *name, int flags);
+
+void dual_timestamp_serialize(FILE *f, const char *name, dual_timestamp *t);
+void dual_timestamp_deserialize(const char *value, dual_timestamp *t);