Cygwin: pty: Switch input and output pipes individually.

- Previously, input and output pipes were switched together between
  the traditional pty and the pseudo console. However, for example,
  if stdin is redirected to another device, it is better to leave
  input pipe traditional pty side even for non-cygwin program. This
  patch realizes such behaviour.

winsup/cygwin/dtable.cc

@@ -147,9 +147,9 @@ dtable::get_debugger_info ()
 void
 dtable::stdio_init ()
 {
-  int chk_order[] = {1, 0, 2};
   for (int i = 0; i < 3; i ++)
     {
+      const int chk_order[] = {1, 0, 2};
       int fd = chk_order[i];
       fhandler_base *fh = cygheap->fdtab[fd];
       if (fh && fh->get_major () == DEV_PTYS_MAJOR)
@@ -169,12 +169,14 @@ dtable::stdio_init ()
 		  FreeConsole ();
 		  if (AttachConsole (ptys->getHelperProcessId ()))
 		    {
-		      ptys->fixup_after_attach (false);
+		      ptys->fixup_after_attach (false, fd);
 		      break;
 		    }
 		}
 	    }
 	}
+      else if (fh && fh->get_major () == DEV_CONS_MAJOR)
+	break;
     }
 
   if (myself->cygstarted || ISSTATE (myself, PID_CYGPARENT))