move gsm_bts_get_cbch() to gsm_data_shared() as its needed in osmo-bts
diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h
index ae6757d..b278309 100644
--- a/openbsc/include/openbsc/gsm_data.h
+++ b/openbsc/include/openbsc/gsm_data.h
@@ -418,6 +418,7 @@
 struct gsm_bts *gsm_bts_alloc_register(struct gsm_network *net,
 					enum gsm_bts_type type,
 					uint8_t tsc, uint8_t bsic);
+
 void set_ts_e1link(struct gsm_bts_trx_ts *ts, uint8_t e1_nr,
 		   uint8_t e1_ts, uint8_t e1_ts_ss);
 
diff --git a/openbsc/include/openbsc/gsm_data_shared.h b/openbsc/include/openbsc/gsm_data_shared.h
index 30f6bc3..54dda1f 100644
--- a/openbsc/include/openbsc/gsm_data_shared.h
+++ b/openbsc/include/openbsc/gsm_data_shared.h
@@ -767,6 +767,9 @@
 uint8_t gsm_ts2chan_nr(const struct gsm_bts_trx_ts *ts, uint8_t lchan_nr);
 uint8_t gsm_lchan2chan_nr(const struct gsm_lchan *lchan);
 
+/* return the gsm_lchan for the CBCH (if it exists at all) */
+struct gsm_lchan *gsm_bts_get_cbch(struct gsm_bts *bts);
+
 /*
  * help with parsing regexps
  */