fix: declare v_exn

Signed-off-by: Rudi Grinberg <[email protected]>

Author: rgrinberg

src/fsevents/fsevents_stubs.c

@@ -33,13 +33,14 @@ CAMLprim value dune_fsevents_runloop_current(value v_unit) {
 
 CAMLprim value dune_fsevents_runloop_run(value v_runloop) {
   CAMLparam1(v_runloop);
+  CAMLlocal1(v_exn);
   dune_runloop *runloop = (dune_runloop *)Nativeint_val(v_runloop);
   caml_release_runtime_system();
   CFRunLoopRun();
   caml_acquire_runtime_system();
   caml_remove_global_root(&runloop->v_exn);
   v_exn = runloop->v_exn;
-  calm_stat_free(runloop);
+  caml_stat_free(runloop);
   if (v_exn != Val_unit)
     caml_raise(v_exn);
   CAMLreturn(Val_unit);