job: add forward declarations

CMakeLists.txt

@@ -275,6 +275,7 @@ list (
     io.cpp
     io.hpp
     iterator.hpp
+    job/fwd.hpp
     job/event.hpp
     job/flag.hpp
     job/monitor.cpp

job/fwd.hpp

@@ -0,0 +1,24 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Copyright 2018 Danny Robson <danny@nerdcruft.net>
+ */
+
+#ifndef CRUFT_UTIL_JOB_FWD_HPP
+#define CRUFT_UTIL_JOB_FWD_HPP
+
+namespace util::job {
+    class queue;
+}
+
+#endif

job/queue.hpp

@@ -11,7 +11,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
- * Copyright 2017 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2017-2018 Danny Robson <danny@nerdcruft.net>
  */
 
 #ifndef CRUFT_UTIL_JOB_QUEUE_HPP