--- a/src/lib/s4/tests/s4/t_transactions.c
+++ b/src/lib/s4/tests/s4/t_transactions.c
@@ -19,7 +19,7 @@
 #include <glib.h>
 #include <glib/gstdio.h>
 
-s4_t *s4;
+extern s4_t *s4;
 s4_val_t *val;
 
 SETUP (Transactions) {