add back-pointer for l1 as part of BTS role.
diff --git a/openbsc/include/openbsc/gsm_data_shared.h b/openbsc/include/openbsc/gsm_data_shared.h
index ab298c9..07ababf 100644
--- a/openbsc/include/openbsc/gsm_data_shared.h
+++ b/openbsc/include/openbsc/gsm_data_shared.h
@@ -247,6 +247,10 @@
 	int nominal_power;		/* in dBm */
 	unsigned int max_power_red;	/* in actual dB */
 
+	struct {
+		void *l1h;
+	} role_bts;
+
 	union {
 		struct {
 			struct {