Fix audio device api table size.

diff --git a/src/lingot-config.h b/src/lingot-config.h
index 6324a6a..0370493 100644
--- a/src/lingot-config.h
+++ b/src/lingot-config.h
@@ -43,7 +43,7 @@ struct _LingotConfig {

 	audio_system_t audio_system;

-	char audio_dev[3][80];
+	char audio_dev[4][80];
 	int sample_rate; // soundcard sample rate.
 	unsigned int oversampling; // oversampling factor.