* cygtls.cc (_threadinfo::init_thread): Add more local reent stdio

initialization.
* dcrt0.cc (initial_env): Can it really be true that XP doesn't allow attaching
a debugger during DLL attach?  Add temporary workaround.
(dll_crt0_0): Ensure that _impure_ptr stdio is initialized before any threads.
(dll_crt0_1): Move _impure_ptr initialization to dll_crt0_0.
* exceptions.cc (try_to_debug): Reinstate old method for looping while
debugging.
* syscalls.cc (_cygwin_istext_for_stdio): Regularize debugging output.  Remove
hopefully extraneous check.
(setmode_helper): Add debugging output for improbable case.  Use "binary"
rather "raw" for consistency.

winsup/cygwin/exceptions.cc

@@ -383,7 +383,8 @@ try_to_debug (bool waitloop)
 	return 1;
       SetThreadPriority (GetCurrentThread (), THREAD_PRIORITY_IDLE);
       while (!being_debugged ())
-	low_priority_sleep (0);
+	Sleep (0);
+      Sleep (2000);
       small_printf ("*** continuing pid %u from debugger call\n",
 		    cygwin_pid (GetCurrentProcessId ()));
     }