apps/system/readline does not use buffered I/O

readline implementation does not use C-buffered I/O, but rather talks to serial driver directly via read(). It includes VT-100 specific editing commands. A more generic readline() should be implemented using termios' tcsetattr() to put the serial driver into a "raw" mode.

This will cause problems if you are using mixed C-buffered I/O with readline and fgetc, for example.