diff --git a/tests/test-runner.c b/tests/test-runner.c
index d07dab15..1bfb0df4 100644
--- a/tests/test-runner.c
+++ b/tests/test-runner.c
@@ -308,6 +308,13 @@ is_debugger_attached(void)
 
 	return rc;
 }
+#else
+static int
+is_debugger_attached(void)
+{
+	/* 0=debugger can't be determined */
+	return 0;
+}
 #endif
 
 int main(int argc, char *argv[])