* pinfo.h (_pinfo::getthread2signal): Remove obsolete function.

* cygtls.h (_threadinfo): Define tid more precisely.
(_threadinfo::operator HANDLE): Define.
* exceptions.cc (_threadinfo::interupt_now): Use _threadinfo HANDLE operator to
derive thread handle.
(setup_handler): Ditto.
* sigproc.cc: Reorganize includes.

winsup/cygwin/pinfo.h

@@ -114,11 +114,6 @@ public:
     sig_mask = mask;
   }
 
-  inline HANDLE getthread2signal ()
-  {
-    return hMainThread;
-  }
-
   void commune_recv ();
   commune_result commune_send (DWORD, ...);
   bool alive ();