Prevent endless loop in x_make_frame_visible.

* xterm.c (x_make_frame_visible): Prevent endless loop when frame
never becomes visible, i.e. using XMonad .

Fixes: debbugs:17237

src/ChangeLog

+2014-04-17  Jan Djärv  <jan.h.d@swipnet.se>
+
+	* xterm.c (x_make_frame_visible): Prevent endless loop when frame
+	never becomes visible, i.e. using XMonad  (Bug#17237).
+
 2014-04-17  Eli Zaretskii  <eliz@gnu.org>
 
 	* xdisp.c (Fline_pixel_height): Don't assume that the current

src/xterm.c

@@ -8899,6 +8899,7 @@ void
 x_make_frame_visible (struct frame *f)
 {
   int original_top, original_left;
+  int tries = 0;
 
   block_input ();
 
@@ -9006,7 +9007,13 @@ x_make_frame_visible (struct frame *f)
 	/* Force processing of queued events.  */
 	x_sync (f);
 
-	/* This hack is still in use at least for Cygwin.  See
+        /* If on another desktop, the deiconify/map may be ignored and the
+           frame never becomes visible.  XMonad does this.
+           Prevent an endless loop.  */
+        if (FRAME_ICONIFIED_P (f) &&  ++tries > 100)
+          break;
+
+       /* This hack is still in use at least for Cygwin.  See
 	   http://lists.gnu.org/archive/html/emacs-devel/2013-12/msg00351.html.
 
 	   Machines that do polling rather than SIGIO have been