* exceptions.cc (sigpacket::process): Move signal_exit processing into...

(_cygtls::signal_exit): ...here.  Close my_readsig and comment on why.
* pinfo.cc (pinfo::exit): Move sigproc_terminate earlier.  Set exiting flag in
lock_process.
* sigproc.cc (my_readsig): Make global.
* sync.cc (muto::exiting_thread): Delete.
(muto::acquire): Delete #if 0'ed code.
* sync.h (muto::exiting_thread): Delete.
(set_exiting_thread): Ditto.
(lock_process::lock_process): Don't worry about setting the exiting thread
since it had no meaning.

winsup/cygwin/sync.cc

@@ -20,7 +20,6 @@ details. */
 
 #undef WaitForSingleObject
 
-DWORD NO_COPY muto::exiting_thread;
 muto NO_COPY lock_process::locker;
 
 void
@@ -76,10 +75,6 @@ int
 muto::acquire (DWORD ms)
 {
   void *this_tls = &_my_tls;
-#if 0
-  if (exiting_thread)
-    return this_tid == exiting_thread;
-#endif
 
   if (tls != this_tls)
     {