Add signal to indicate any track rec-arm change

libs/ardour/ardour/session.h

@@ -409,6 +409,8 @@ public:
 	*/
 	PBD::Signal0<void> RecordArmStateChanged; /* signals changes in recording arming */
 
+	PBD::Signal0<void> UpdateRouteRecordState; /* signals potential change in route recording arming */
+
 	/* Emited when session is loaded */
 	PBD::Signal0<void> SessionLoaded;
 

libs/ardour/session.cc

@@ -6143,6 +6143,7 @@ Session::update_route_record_state ()
 		RecordArmStateChanged ();
 	}
 
+	UpdateRouteRecordState ();
 }
 
 void