add config file parameter to specify the desired port when using the ALSA music driver

svn-id: r11583

README

@@ -629,7 +629,8 @@ sequencer support does not work, you can always fall back on Adlib emulation.
 7.4.1 Playing sound with ALSA sequencer:                        [UNIX ONLY]
 ----- ----------------------------------
 If you have installed the ALSA driver with the sequencer support, then
-set the environment variable "SCUMMVM_PORT" to your sequencer port - e.g. 65:0
+set the environment variable SCUMMVM_PORT or the config file parameter
+alsa_port to your sequencer port. The default is "65:0".
 
 Here is a little howto on how to use the ALSA sequencer with your soundcard.
 In all cases, to have a list of all the sequencer ports you have, try the
@@ -825,6 +826,8 @@ The following keywords are recognized:
         joystick_num    number   Number of joystick device to use for input
         master_volume   number   The master volume setting (0-255)
         music_driver    string   The music engine to use.
+        alsa_port       string   Port to use for output when using the
+                                 ALSA music driver.
         music_volume    number   The music volume setting (0-255)
         multi_midi      bool     If true, enable combination Adlib and native
                                  MIDI.

backends/midi/alsa.cpp

@@ -29,6 +29,8 @@
 
 #include "stdafx.h"
 #include "common/util.h"
+#include "common/config-manager.h"
+
 #include <alsa/asoundlib.h>
 
 /*
@@ -84,8 +86,8 @@ int MidiDriver_ALSA::open() {
 	_isOpen = true;
 
 	if (!(var = getenv("SCUMMVM_PORT"))) {
-		// default alsa port if none specified
-		if (parse_addr("65:0", &seq_client, &seq_port) < 0) {
+		// use config option if no var specified
+		if (parse_addr(ConfMan.get("alsa_port").c_str(), &seq_client, &seq_port) < 0) {
 			error("Invalid port %s", var);
 			return -1;
 		}

base/gameDetector.cpp

@@ -177,6 +177,9 @@ GameDetector::GameDetector() {
 	ConfMan.registerDefault("debuglevel", 0);
 	ConfMan.registerDefault("joystick_num", -1);
 	ConfMan.registerDefault("confirm_exit", false);
+#ifdef USE_ALSA
+	ConfMan.registerDefault("alsa_port", "65:0");
+#endif
 
 	_dumpScripts = false;