Cygwin: console: Set ENABLE_PROCESSED_INPUT when disable_master_thread

Currently, ENABLE_PROCESSED_INPUT is set in set_input_mode() if
master_thread_suspended is true. This enables Ctrl-C handling when
cons_master_thread is suspended, since Ctrl-C is normally handled
by cons_master_thread.
However, when disable_master_thread is true, ENABLE_PROCESSED_INPUT
is not set, even though this also disables Ctrl-C handling in
cons_master_thread. Due to this bug, the command
  C:\cygwin64\bin\sleep 10 < NUL
in the Command Prompt cannot be terminated with Ctrl-C.

This patch addresses the issue by setting ENABLE_PROCESSED_INPUT
when either disable_master_thread or master_thread_suspended is true.

This bug also affects cases where non-Cygwin Git (Git for Windows)
launches Cygwin SSH. In such cases, SSH also cannot be terminated
with Ctrl-C.

Addresses: git-for-windows/git#5682 (comment)
Fixes: 746c811 ("Cygwin: console: Allow pasting very long text input.")
Reported-by: Johannes Schindelin <[email protected]>
Signed-off-by: Takashi Yano <[email protected]>
(cherry picked from commit 476135a24506dd624eb46b50fd634fcd740008ba)
Cherry-picked-from: 61cc419 (Cygwin: console: Set ENABLE_PROCESSED_INPUT when disable_master_thread, 2025-07-01))
Signed-off-by: Johannes Schindelin <[email protected]>

Author: tyan0

winsup/cygwin/fhandler/console.cc

@@ -831,7 +831,7 @@ fhandler_console::set_input_mode (tty::cons_mode m, const termios *t,
       break;
     case tty::cygwin:
       flags |= ENABLE_WINDOW_INPUT;
-      if (con.master_thread_suspended)
+      if (con.master_thread_suspended || con.disable_master_thread)
 	flags |= ENABLE_PROCESSED_INPUT;
       if (wincap.has_con_24bit_colors () && !con_is_legacy)
 	flags |= ENABLE_VIRTUAL_TERMINAL_INPUT;