Command-line game: get default ai_algorithm from config

Do not use a hard-coded value set to the RCA AI.

src/game_initialization/connect_engine.cpp

@@ -490,7 +490,7 @@ void connect_engine::start_game()
 	send_to_server(config("start_game"));
 }
 
-void connect_engine::start_game_commandline(const commandline_options& cmdline_opts)
+void connect_engine::start_game_commandline(const commandline_options& cmdline_opts, const config& game_config)
 {
 	DBG_MP << "starting a new game in commandline mode" << std::endl;
 
@@ -532,9 +532,10 @@ void connect_engine::start_game_commandline(const commandline_options& cmdline_o
 			}
 		}
 
-		// Set AI algorithm to RCA AI for all sides,
+		// Set AI algorithm to default for all sides,
 		// then override if commandline option was given.
-		side->set_ai_algorithm("ai_default_rca");
+		std::string ai_algorithm = game_config.child("ais")["default_ai_algorithm"].str();
+		side->set_ai_algorithm(ai_algorithm);
 		if(cmdline_opts.multiplayer_algorithm) {
 			for(const mp_option& option : *cmdline_opts.multiplayer_algorithm) {
 

src/game_initialization/connect_engine.hpp

@@ -63,7 +63,7 @@ class connect_engine
 
 	bool can_start_game() const;
 	void start_game();
-	void start_game_commandline(const commandline_options& cmdline_opts);
+	void start_game_commandline(const commandline_options& cmdline_opts, const config& game_config);
 
 	void leave_game();
 

src/game_initialization/multiplayer.cpp

@@ -763,7 +763,7 @@ void start_local_game_commandline(const config& game_config, saved_game& state,
 		ng::connect_engine_ptr connect_engine(new ng::connect_engine(state, true, nullptr));
 
 		// Update the parameters to reflect game start conditions
-		connect_engine->start_game_commandline(cmdline_opts);
+		connect_engine->start_game_commandline(cmdline_opts, game_config);
 	}
 
 	if(resources::recorder && cmdline_opts.multiplayer_label) {