[newlib-cygwin] Cygwin: signals: make setcontext work from signal handlers

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=c5f9eed1c045ad05e968c9a9b8fb22b1d46cd8ea

commit c5f9eed1c045ad05e968c9a9b8fb22b1d46cd8ea
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. */