[newlib-cygwin/cygwin-3_0-branch] Cygwin: signals: make setcontext work from signal handlers

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=367d588e59bd384bf7a50ed68ec8fabfc02ff12e

commit 367d588e59bd384bf7a50ed68ec8fabfc02ff12e
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Thu Apr 4 21:25:47 2019 +0200

    Cygwin: signals:  make setcontext work from signal handlers
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 winsup/cygwin/exceptions.cc | 1 +
 1 file changed, 1 insertion(+)

diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
index a9b3781..0aaeee5 100644
--- a/winsup/cygwin/exceptions.cc
+++ b/winsup/cygwin/exceptions.cc
@@ -1867,6 +1867,7 @@ setcontext (const ucontext_t *ucp)
 {
   PCONTEXT ctx = (PCONTEXT) &ucp->uc_mcontext;
   _my_tls.sigmask = ucp->uc_sigmask;
+  _my_tls.incyg = true;
 #ifdef __x86_64__
   /* Apparently a call to NtContinue works on 64 bit as well, but using
      RtlRestoreContext is the blessed way. */