add msgb_set_talloc_ctx() to set the talloc context for msgb allocations
diff --git a/src/msgb.c b/src/msgb.c
index d2c167a..f9841ed 100644
--- a/src/msgb.c
+++ b/src/msgb.c
@@ -98,3 +98,8 @@
 {
 	return msg->len;
 }
+
+void msgb_set_talloc_ctx(void *ctx)
+{
+	tall_msgb_ctx = ctx;
+}