[zenity] Do not crash in --forms --add-list without column values

[Arx Henrique Pereira da Cruz <arxcruz src gnome org>]

commit d845087870a8994dfb0842bf72ca7a5d5138fbef
Author: Alexandre Rostovtsev <tetromino gentoo org>
Date:   Sat May 19 20:53:27 2012 -0400

    Do not crash in --forms --add-list without column values
    
    Be a bit more user friendly, and instead of crashing, add a default
    column name if the user forgot to use --column-values with a --forms list.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=676406

 src/option.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/src/option.c b/src/option.c
index 7fdb7f1..334ec86 100644
--- a/src/option.c
+++ b/src/option.c
@@ -1918,7 +1918,9 @@ zenity_forms_post_callback (GOptionContext *context,
         results->forms_data->column_values = g_slist_append (results->forms_data->column_values, values);
         values = zenity_forms_list_values[++i];
       }
-    }
+    } else
+      results->forms_data->column_values = g_slist_append (NULL, "column");
+
     if (zenity_forms_date_format)
       results->forms_data->date_format = zenity_forms_date_format;
     else