+ *
+ * @param fd File descriptor of stdin (normally 0)
+ * @param allow_sigs Allow Ctrl-C, Ctrl-Z to generate signals rather than
+ * be handled by U-Boot
+ */
+void os_tty_raw(int fd, bool allow_sigs);
+
+/**
+ * Restore the tty to its original mode
+ *
+ * Call this to restore the original terminal mode, after it has been changed
+ * by os_tty_raw(). This is an internal function.