[glabels] Added dummy window as parent in warning and critical error handlers.

[Jim Evins <jimevins src gnome org>]

commit b66c0076908a706235af21b2c1d3ef04a6ba1f7f
Author: Jim Evins <evins snaught com>
Date:   Thu Oct 23 20:45:12 2014 -0400

    Added dummy window as parent in warning and critical error handlers.
    
    In gtk 3.14, creating a message dialog without a parent window
    causes a crash.  Unfortunately this causes the original error or
    warning message from being seen by the user.

 src/critical-error-handler.c |    4 +++-
 src/warning-handler.c        |    5 ++++-
 2 files changed, 7 insertions(+), 2 deletions(-)
---
diff --git a/src/critical-error-handler.c b/src/critical-error-handler.c
index 0d9fed1..d7ab99d 100644
--- a/src/critical-error-handler.c
+++ b/src/critical-error-handler.c
@@ -61,9 +61,11 @@ critical_error_handler (const gchar    *log_domain,
                         const gchar    *message,
                         gpointer        user_data)
 {
+        GtkWidget *dummy_window;
         GtkWidget *dialog;
 
-        dialog = gtk_message_dialog_new (NULL,
+        dummy_window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+        dialog = gtk_message_dialog_new (GTK_WINDOW (dummy_window),
                                          GTK_DIALOG_MODAL,
                                          GTK_MESSAGE_ERROR,
                                          GTK_BUTTONS_NONE,
diff --git a/src/warning-handler.c b/src/warning-handler.c
index 8f5f1b7..a7cb5f8 100644
--- a/src/warning-handler.c
+++ b/src/warning-handler.c
@@ -60,9 +60,11 @@ warning_handler (const gchar    *log_domain,
                  const gchar    *message,
                  gpointer        user_data)
 {
+        GtkWidget *dummy_window;
         GtkWidget *dialog;
 
-        dialog = gtk_message_dialog_new (NULL,
+        dummy_window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+        dialog = gtk_message_dialog_new (GTK_WINDOW (dummy_window),
                                          GTK_DIALOG_MODAL,
                                          GTK_MESSAGE_WARNING,
                                          GTK_BUTTONS_CLOSE,
@@ -73,6 +75,7 @@ warning_handler (const gchar    *log_domain,
         gtk_dialog_run (GTK_DIALOG (dialog));
 
        gtk_widget_destroy (GTK_WIDGET (dialog));
+        gtk_widget_destroy (GTK_WIDGET (dummy_window));
 }