freetdm: ftmod_libpri - add support for RINGING state

libs/freetdm/src/ftmod/ftmod_libpri/ftmod_libpri.c

@@ -462,7 +462,7 @@ static ftdm_state_map_t isdn_state_map = {
 			ZSD_INBOUND,
 			ZSM_UNACCEPTABLE,
 			{FTDM_CHANNEL_STATE_RING, FTDM_END},
-			{FTDM_CHANNEL_STATE_HANGUP, FTDM_CHANNEL_STATE_TERMINATING, FTDM_CHANNEL_STATE_PROGRESS, FTDM_CHANNEL_STATE_PROGRESS_MEDIA, FTDM_CHANNEL_STATE_UP, FTDM_END}
+			{FTDM_CHANNEL_STATE_HANGUP, FTDM_CHANNEL_STATE_TERMINATING, FTDM_CHANNEL_STATE_RINGING, FTDM_CHANNEL_STATE_PROGRESS_MEDIA, FTDM_CHANNEL_STATE_UP, FTDM_END}
 		},
 		{
 			ZSD_INBOUND,
@@ -479,7 +479,7 @@ static ftdm_state_map_t isdn_state_map = {
 		{
 			ZSD_INBOUND,
 			ZSM_UNACCEPTABLE,
-			{FTDM_CHANNEL_STATE_PROGRESS, FTDM_CHANNEL_STATE_PROGRESS_MEDIA, FTDM_END},
+			{FTDM_CHANNEL_STATE_RINGING, FTDM_CHANNEL_STATE_PROGRESS_MEDIA, FTDM_END},
 			{FTDM_CHANNEL_STATE_HANGUP, FTDM_CHANNEL_STATE_TERMINATING, FTDM_CHANNEL_STATE_PROGRESS_MEDIA, 
 			 FTDM_CHANNEL_STATE_CANCEL, FTDM_CHANNEL_STATE_UP, FTDM_END},
 		},
@@ -537,6 +537,8 @@ static __inline__ void state_advance(ftdm_channel_t *chan)
 		break;
 
 	case FTDM_CHANNEL_STATE_PROGRESS:
+	/* RINGING is an alias for PROGRESS state in inbound calls ATM */
+	case FTDM_CHANNEL_STATE_RINGING:
 		{
 			if (ftdm_test_flag(chan, FTDM_CHANNEL_OUTBOUND)) {
 				sig.event_id = FTDM_SIGEVENT_PROGRESS;