fix various compiler warnings

sgsn_libgtp.c: missing include, for asn1str_to_u32()

iu_cs.c: missing include, for subscr_name()

osmo_bsc_vty.c: int/pointer conversions
(note: this was discussed on the list to be solved by passing a pointer
instead. Until then...)

iudummy.c: opaque struct declarations

openbsc/src/gprs/sgsn_libgtp.c

@@ -52,6 +52,8 @@
 
 #include <osmocom/ranap/ranap_ies_defs.h>
 
+#include <asn1c/asn1helpers.h>
+
 #include <gtp.h>
 #include <pdp.h>
 

openbsc/src/libmsc/iu_cs.c

@@ -6,6 +6,7 @@
 #include <openbsc/gsm_data.h>
 #include <openbsc/msc_api.h>
 #include <openbsc/iu.h>
+#include <openbsc/gsm_subscriber.h>
 
 /* For A-interface see libbsc/bsc_api.c subscr_con_allocate() */
 struct gsm_subscriber_connection *subscr_conn_allocate_iu(struct gsm_network *network,

openbsc/src/osmo-bsc/osmo_bsc_vty.c

@@ -43,7 +43,7 @@ static struct osmo_bsc_data *osmo_bsc_data(struct vty *vty)
 
 static struct osmo_msc_data *osmo_msc_data(struct vty *vty)
 {
-	return osmo_msc_data_find(bsc_gsmnet, (int) vty->index);
+	return osmo_msc_data_find(bsc_gsmnet, (long int) vty->index);
 }
 
 static struct cmd_node bsc_node = {
@@ -70,7 +70,7 @@ DEFUN(cfg_net_msc, cfg_net_msc_cmd,
 		return CMD_WARNING;
 	}
 
-	vty->index = (void *) index;
+	vty->index = (void *)(long int)index;
 	vty->node = MSC_NODE;
 	return CMD_SUCCESS;
 }

openbsc/tests/libiudummy/iudummy.c

@@ -4,6 +4,10 @@
 #include <osmocom/vty/logging.h>
 #include <osmocom/core/msgb.h>
 
+struct msgb;
+struct ue_conn_ctx;
+struct gsm_auth_tuple;
+
 int iu_tx(struct msgb *msg, uint8_t sapi)
 {
 	LOGP(DLGLOBAL, LOGL_INFO, "iu_tx() dummy called, NOT transmitting %d bytes: %s\n",