Fix #84: Reset TTY w/ stty() before taking any pre-getty action

This patch moves the stty() function from getty.c to a separate file so
it can be called from exec.c as well.  The fix to #84 is simply to call
stty() in prepare_tty(), which is shared by run_getty() and run_getty2()
and called before "Please press Enter ...".

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

src/helpers.h

@@ -48,6 +48,8 @@ struct fstab *getfsent  (void);
 
 char   *strip_line      (char *line);
 
+int     stty            (int fd, unsigned int speed);
+
 int     pid_alive       (pid_t pid);
 char   *pid_get_name    (pid_t pid, char *name, size_t len);