[newlib-cygwin] Cygwin: pty: Make rlwrap work with cmd.exe.

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=5176afeb7d27339ee7ce8f1f9c8c0941da8ca4c2

commit 5176afeb7d27339ee7ce8f1f9c8c0941da8ca4c2
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Mon Apr 19 20:51:53 2021 +0900

    Cygwin: pty: Make rlwrap work with cmd.exe.
    
    - After the commit 919dea66, "rlwrap cmd" fails to start pseudo
      console. This patch fixes the issue.

Diff:
---
 winsup/cygwin/fhandler_tty.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
index ba9f4117f..d44728795 100644
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -1170,6 +1170,8 @@ fhandler_pty_slave::reset_switch_to_pcon (void)
     }
   if (isHybrid)
     return;
+  if (get_ttyp ()->pcon_start)
+    return;
   WaitForSingleObject (pcon_mutex, INFINITE);
   if (!pcon_pid_self (get_ttyp ()->pcon_pid)
       && pcon_pid_alive (get_ttyp ()->pcon_pid))