diff --git a/src/plugins/projectexplorer/task.cpp b/src/plugins/projectexplorer/task.cpp
index 63574c74d606a48a3c7699e2f6441b20ca78410d..a1571b91b8a98273af6c8fac10f284bc354f930a 100644
--- a/src/plugins/projectexplorer/task.cpp
+++ b/src/plugins/projectexplorer/task.cpp
@@ -65,6 +65,29 @@ bool operator==(const Task &t1, const Task &t2)
     return t1.taskId == t2.taskId;
 }
 
+bool operator<(const Task &a, const Task &b)
+{
+    if (a.type != b.type) {
+        if (a.type == ProjectExplorer::Task::Error)
+            return true;
+        if (b.type == ProjectExplorer::Task::Error)
+            return false;
+        if (a.type == ProjectExplorer::Task::Warning)
+            return true;
+        if (b.type == ProjectExplorer::Task::Warning)
+            return false;
+        // Can't happen
+        return true;
+    } else {
+        if (a.category < b.category)
+            return true;
+        if (b.category < a.category)
+            return false;
+        return a.taskId < b.taskId;
+    }
+}
+
+
 uint qHash(const Task &task)
 {
     return task.taskId;
diff --git a/src/plugins/projectexplorer/task.h b/src/plugins/projectexplorer/task.h
index ad5f3ec9a6c24bd230ae9ceebb87bc01f247c2b1..66c22b64df30f9951420fef0d2e19e3189e6f065 100644
--- a/src/plugins/projectexplorer/task.h
+++ b/src/plugins/projectexplorer/task.h
@@ -76,8 +76,10 @@ private:
     static unsigned int s_nextId;
 };
 
-bool operator==(const Task &t1, const Task &t2);
-uint qHash(const Task &task);
+bool PROJECTEXPLORER_EXPORT operator==(const Task &t1, const Task &t2);
+uint PROJECTEXPLORER_EXPORT qHash(const Task &task);
+
+bool PROJECTEXPLORER_EXPORT operator<(const Task &a, const Task &b);
 
 } //namespace ProjectExplorer