+void filter_environ(const char *prefix);
+
+bool tty_is_vc(const char *tty);
+const char *default_term_for_tty(const char *tty);
+
+int detect_vm(const char **id);
+int detect_container(const char **id);
+int detect_virtualization(const char **id);
+
+void execute_directory(const char *directory, DIR *_d, char *argv[]);
+
+int kill_and_sigcont(pid_t pid, int sig);
+
+bool nulstr_contains(const char*nulstr, const char *needle);
+