add missing #include line to gsm_data_shared.h
gsm_data_shared.h references structures defined in abis/e1_input.h
diff --git a/openbsc/include/openbsc/gsm_data_shared.h b/openbsc/include/openbsc/gsm_data_shared.h
index a639a1c..ca88fed 100644
--- a/openbsc/include/openbsc/gsm_data_shared.h
+++ b/openbsc/include/openbsc/gsm_data_shared.h
@@ -17,6 +17,8 @@
#include <osmocom/gsm/protocol/gsm_08_58.h>
#include <osmocom/gsm/protocol/gsm_12_21.h>
+#include <osmocom/abis/e1_input.h>
+
struct osmo_msc_data;
struct osmo_bsc_sccp_con;
struct gsm_sms_queue;