[newlib-cygwin] Cygwin: pty: Avoid detach console in the process running as service.

[Ken Brown]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=9bedd6807dc3a1ad6c80e62a6a7aae27ca769de0

commit 9bedd6807dc3a1ad6c80e62a6a7aae27ca769de0
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Wed Oct 16 21:34:08 2019 +0900

    Cygwin: pty: Avoid detach console in the process running as service.

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 1095c82..dbb035f 100644
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -1048,6 +1048,8 @@ fhandler_pty_slave::try_reattach_pcon (void)
 
   /* Do not detach from the console because re-attaching will
      fail if helper process is running as service account. */
+  if (get_ttyp()->attach_pcon_in_fork)
+    return false;
   if (pcon_attached_to >= 0 &&
       cygwin_shared->tty[pcon_attached_to]->attach_pcon_in_fork)
     return false;