Add talloc context introspection via VTY

This requires libosmocore with Change-Id
I43fc42880b22294d83c565ae600ac65e4f38b30d or later.

Change-Id: I460efff3a3dfa2c7d955871aca78b37552a29aff
diff --git a/ggsn/ggsn.c b/ggsn/ggsn.c
index caf6151..df071d2 100644
--- a/ggsn/ggsn.c
+++ b/ggsn/ggsn.c
@@ -56,6 +56,7 @@
 #include <osmocom/vty/stats.h>
 #include <osmocom/vty/ports.h>
 #include <osmocom/vty/command.h>
+#include <osmocom/vty/misc.h>
 #include <osmocom/gsm/apn.h>
 
 #include "../lib/tun.h"
@@ -1062,6 +1063,7 @@
 
 	tall_ggsn_ctx = talloc_named_const(NULL, 0, "OsmoGGSN");
 	msgb_talloc_ctx_init(tall_ggsn_ctx, 0);
+	g_vty_info.tall_ctx = tall_ggsn_ctx;
 
 	/* Handle keyboard interrupt SIGINT */
 	signal(SIGINT, &signal_handler);
@@ -1076,6 +1078,7 @@
 
 	vty_init(&g_vty_info);
 	logging_vty_add_cmds(NULL);
+	osmo_talloc_vty_add_cmds();
 	osmo_stats_vty_add_cmds(&log_info);
 	ggsn_vty_init();
 	ctrl_vty_init(tall_ggsn_ctx);