diff --git a/runtime/tests/test_idle_skip_store_counter.c b/runtime/tests/test_idle_skip_store_counter.c
index 93bd6406..2a44c349 100644
--- a/runtime/tests/test_idle_skip_store_counter.c
+++ b/runtime/tests/test_idle_skip_store_counter.c
@@ -27,6 +27,7 @@ int g_ls_mode = 0;
 int g_precise_mode = 0;
 int g_psx_call_bail = 0;
 int g_boot_state_cpu_timing_restored = 0;   /* boot_state.c, read by psx_cycles.c */
+int psx_mod_host_output_scope(void) { return 0; }   /* mod_runtime.cpp */
 uint32_t i_mask = 0;
 uint64_t g_guest_store_count = 0;
 uint64_t g_mmio_access_count = 0;