Cygwin: pty: Fix FLUSHO handling

Previsouly, FLUSHO did not work correctly.
 1) Even when FLUSHO is set, read() returns with undesired data in
    the pipe if select() is called in advance.
 2) FLUSHO is toggled even in the case pseudo console enabled.
Due to these problems, read data in the pty master was partially
lost when Ctrl-O is pressed.

With this patch, the mask_flusho flag, that was introduced by the
commit 9677efcf005a and caused the issue 1), has been dropped and
select() and read() for pty master discards the pipe data instead
if FLUSHO flag is set.  In addition, FLUSHO handling in the case
pseudo console activated is disabled.

Addresses: https://cygwin.com/pipermail/cygwin/2025-August/258717.html
Fixes: 2cab4d0bb4af ("Cygwin: pty, console: Refactor the code processing special keys.")
Fixes: 9677efcf005a ("Cygwin: pty: Make FLUSHO and Ctrl-O work.")
Reported-by: Reported-by: Thomas Wolff <towo@towo.net>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>

0 files changed, 0 insertions, 0 deletions