make notification stacking optional

see #137

dunstrc

@@ -27,6 +27,9 @@
     # Show how many messages are currently hidden (because of geometry)
     indicate_hidden = yes
 
+    # Stack duplicate Messages or show them individually
+    stack_duplicates = yes
+
     # alignment of message text.
     # Possible values are "left", "center" and "right"
     alignment = left

notification.c

@@ -315,6 +315,7 @@ int notification_init(notification * n, int id)
         n->dup_count = 0;
 
         /* check if n is a duplicate */
+        if (settings.stack_duplicates) {
                 for (GList * iter = g_queue_peek_head_link(queue); iter;
                      iter = iter->next) {
                         notification *orig = iter->data;
@@ -365,6 +366,7 @@ int notification_init(notification * n, int id)
                                 return orig->id;
                         }
                 }
+        }
 
         /* urgency > CRIT -> array out of range */
         n->urgency = n->urgency > CRIT ? CRIT : n->urgency;

settings.c

@@ -175,6 +175,9 @@ void load_settings(char *cmdline_config_path)
                 }
         }
 
+        settings.stack_duplicates = option_get_bool("global", "stack_duplicates",
+                        "-stack_duplicates", true, "Merge multiple notifications with the same content");
+
         settings.startup_notification =
             option_get_bool("global", "startup_notification",
                             "-startup_notification", false,

settings.h

@@ -4,6 +4,7 @@
 typedef struct _settings {
         bool print_notifications;
         bool allow_markup;
+        bool stack_duplicates;
         char *font;
         char *normbgcolor;
         char *normfgcolor;