SMPP: Implement SMPP Osmocom Estensions on MO-SMS

An ESME can now be configured in the VTY to enable osmocom-extensions,
which will add vendor-specific SMPP TLVs for RxLev/RxQual/ARFCN/IMEI and
transmit power to the SMPP DELIVER-SM message type.
diff --git a/openbsc/src/libmsc/gsm_04_11.c b/openbsc/src/libmsc/gsm_04_11.c
index 9e00bda..2fc250b 100644
--- a/openbsc/src/libmsc/gsm_04_11.c
+++ b/openbsc/src/libmsc/gsm_04_11.c
@@ -57,7 +57,8 @@
 
 #ifdef BUILD_SMPP
 #include "smpp_smsc.h"
-extern int smpp_try_deliver(struct gsm_sms *sms);
+extern int smpp_try_deliver(struct gsm_sms *sms,
+			    struct gsm_subscriber_connection *conn);
 #endif
 
 void *tall_gsms_ctx;
@@ -395,7 +396,7 @@
 	gsms->receiver = subscr_get_by_extension(conn->bts->network, gsms->dst.addr);
 	if (!gsms->receiver) {
 #ifdef BUILD_SMPP
-		rc = smpp_try_deliver(gsms);
+		rc = smpp_try_deliver(gsms, conn);
 		if (rc == 1) {
 			rc = 1; /* cause 1: unknown subscriber */
 			osmo_counter_inc(conn->bts->network->stats.sms.no_receiver);