* cygtls.h (struct _cygtls::thread_handle): Remove/revert.

* sigproc.h (struct sipacket::thread_handle): Put thread_handle here.
* sigproc.cc (sigproc_terminate): Move setting of thread_handle...
(sig_send): ...to here.  Put it in packet being sent.  Only close pack.wakeup
when we're waiting for completion.
(wait_sig): Use thread_handle directly from received packet.

winsup/cygwin/sigproc.h

@@ -47,6 +47,7 @@ struct sigpacket
   union
   {
     HANDLE wakeup;
+    HANDLE thread_handle;
     struct sigpacket *next;
   };
   int __stdcall process () __attribute__ ((regparm (1)));