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

* 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.