e6dabba58b
With TIOCPKT enabled, each piece of output is preceded by a zero byte on the PTY master. In addition, a non-zero byte is a flags field that conveys information about changes on the pseudoterminal. This patch implements the former, but not the latter. That is enough to get telnetd(8) going, however. TIOCPKT support may be extended later. Change-Id: I6ef9cc8cf1b4406147b088400fc8499684b62a30