* debug.cc (makethread): Eliminate unneeded function call.

* miscfuncs.cc (tls_ix): Predefine.
* perthread.h (set_reent): Eliminate.
(get_reent): Ditto.
* winbase.h (my_tlsalloc): Use global stack base pointer.  Set newly allocated
location to NULL.
(my_tlssetvalue): Use global stack base pointer.
(my_tlsgetvalue): Ditto.

winsup/cygwin/debug.cc

@@ -95,7 +95,6 @@ thread_stub (VOID *arg)
      SIGSEGV or SIGFPE. */
   init_exceptions (&except_entry);
 
-  set_reent (user_data->impure_ptr);
   ExitThread (threadfunc (threadarg));
 }