diff --git a/src/osmo-bts-sysmo/femtobts.h b/src/osmo-bts-sysmo/femtobts.h
index 7e45578..3a428ee 100644
--- a/src/osmo-bts-sysmo/femtobts.h
+++ b/src/osmo-bts-sysmo/femtobts.h
@@ -18,22 +18,22 @@
 	L1P_T_IND,
 };
 
-const enum l1prim_type femtobts_l1prim_type[GsmL1_PrimId_NUM];
-const struct value_string femtobts_l1prim_names[GsmL1_PrimId_NUM+1];
-const GsmL1_PrimId_t femtobts_l1prim_req2conf[GsmL1_PrimId_NUM];
+extern const enum l1prim_type femtobts_l1prim_type[GsmL1_PrimId_NUM];
+extern const struct value_string femtobts_l1prim_names[GsmL1_PrimId_NUM+1];
+extern const GsmL1_PrimId_t femtobts_l1prim_req2conf[GsmL1_PrimId_NUM];
 
-const enum l1prim_type femtobts_sysprim_type[SuperFemto_PrimId_NUM];
-const struct value_string femtobts_sysprim_names[SuperFemto_PrimId_NUM+1];
-const SuperFemto_PrimId_t femtobts_sysprim_req2conf[SuperFemto_PrimId_NUM];
+extern const enum l1prim_type femtobts_sysprim_type[SuperFemto_PrimId_NUM];
+extern const struct value_string femtobts_sysprim_names[SuperFemto_PrimId_NUM+1];
+extern const SuperFemto_PrimId_t femtobts_sysprim_req2conf[SuperFemto_PrimId_NUM];
 
-const struct value_string femtobts_l1sapi_names[GsmL1_Sapi_NUM+1];
-const struct value_string femtobts_l1status_names[GSML1_STATUS_NUM+1];
+extern const struct value_string femtobts_l1sapi_names[GsmL1_Sapi_NUM+1];
+extern const struct value_string femtobts_l1status_names[GSML1_STATUS_NUM+1];
 
-const struct value_string femtobts_tracef_names[29];
+extern const struct value_string femtobts_tracef_names[29];
 
-const struct value_string femtobts_tch_pl_names[15];
+extern const struct value_string femtobts_tch_pl_names[15];
 
-const struct value_string femtobts_dir_names[6];
+extern const struct value_string femtobts_dir_names[6];
 
 enum pdch_cs {
 	PDCH_CS_1,
@@ -52,6 +52,6 @@
 	_NUM_PDCH_CS
 };
 
-const uint8_t pdch_msu_size[_NUM_PDCH_CS];
+extern const uint8_t pdch_msu_size[_NUM_PDCH_CS];
 
 #endif /* FEMTOBTS_H */