+void filter_environ(const char *prefix);
+
+bool tty_is_vc(const char *tty);
+const char *default_term_for_tty(const char *tty);
+
+bool running_in_vm(void);
+
+void execute_directory(const char *directory, DIR *_d, char *argv[]);
+
+#define NULSTR_FOREACH(i, l) \