* cygtls.cc (_cygtls::init_thread): Set __sdidinit to negative value to

indicate that it is "special".
* thread.cc (pthread::exit): If __sdidinit is < 0, it was never really
initialized so reset it to 0 before calling _reclaim_reent.

winsup/cygwin/thread.cc

@@ -355,6 +355,8 @@ pthread::exit (void *value_ptr)
       mutex.unlock ();
     }
 
+  if (_my_tls.local_clib.__sdidinit < 0)
+    _my_tls.local_clib.__sdidinit = 0;
   (_reclaim_reent) (_REENT);