[gtk+] gdk: Use a better error message

[Emmanuele Bassi <ebassi src gnome org>]

commit 7cee6c5cc6f35d9ed453f943686c0b21e86b4a3e
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Fri Feb 27 21:00:16 2015 +0000

    gdk: Use a better error message
    
    Having "Assertion failed: success" on the console is not going to help
    anyone.

 gdk/win32/gdkdisplay-win32.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/gdk/win32/gdkdisplay-win32.c b/gdk/win32/gdkdisplay-win32.c
index b4f004d..0a75f45 100644
--- a/gdk/win32/gdkdisplay-win32.c
+++ b/gdk/win32/gdkdisplay-win32.c
@@ -355,7 +355,12 @@ inner_clipboard_window_procedure (HWND   hwnd,
         GdkWindow *owner;
 
         success = OpenClipboard (hwnd);
-        g_return_val_if_fail (success, 0);
+        if (!success)
+          {
+            g_warning ("Failed to OpenClibpboard on window handle %p", hwnd);
+            return 0;
+          }
+
         hwndOwner = GetClipboardOwner ();
         owner = gdk_win32_window_lookup_for_display (_gdk_display, hwndOwner);
         if (owner == NULL)