Changeset 5eb7da97 in rtems for c

Disable IXON by default based on comment from Eric Norum
<e.norum@…> and concerns from Thomas Doerfler
<td@…> when he submitted the patch:

Since enabling XON/XOFF has such a major performance hit on `smart' output
devices I think it should be *off* by default. I think some thought should
be given to adding hooks for hardware that can support XON/XOFF without
software intervention, or for hardware like the 68360 SCC's that can use
large buffers, but still handle special characters immediately.

The patch you sent is a very good start, though. I just think that the
software flow control should be off -- to match the way the serial I/O
support has worked up until now.