[newlib-cygwin] Cygwin: pty: Fix deadlock caused by Ctrl-C in setup_pseudoconsole().

[Takashi Yano <tyan0@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=98b6f23d98c5c75f96abd91860a2dccbebe7ffda

commit 98b6f23d98c5c75f96abd91860a2dccbebe7ffda
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Mon Apr 18 19:56:14 2022 +0900

    Cygwin: pty: Fix deadlock caused by Ctrl-C in setup_pseudoconsole().
    
    - If Ctrl-C is pressed just after setup_pseudoconsole() is called,
      mintty stops to respond a while when CPU load is high. This patch
      fixes the issue.
    
    Addresses: https://cygwin.com/pipermail/cygwin/2022-April/251272.html

Diff:
---
 winsup/cygwin/spawn.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/winsup/cygwin/spawn.cc b/winsup/cygwin/spawn.cc
index 400457117..c9e1fb6d2 100644
--- a/winsup/cygwin/spawn.cc
+++ b/winsup/cygwin/spawn.cc
@@ -679,8 +679,12 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
 	  HANDLE h_stdin = handle (fileno_stdin, false);
 	  if (h_stdin == ptys_primary->get_handle_nat ())
 	    stdin_is_ptys = true;
+	  if (reset_sendsig)
+	    myself->sendsig = myself->exec_sendsig;
 	  ptys_primary->setup_for_non_cygwin_app (nopcon, envblock,
 						  stdin_is_ptys);
+	  if (reset_sendsig)
+	    myself->sendsig = NULL;
 	  ptys_primary->get_duplicated_handle_set (&ptys_handle_set);
 	  ptys_ttyp = (tty *) ptys_primary->tc ();
 	  ptys_need_cleanup = true;