May need more stack space in `mrb_funcall_with_block`; fix
@@ -455,7 +455,7 @@ mrb_funcall_with_block(mrb_state *mrb, mrb_value self, mrb_sym mid, mrb_int argc
}
else if (argc >= CALL_MAXARGS) {
mrb_value args = mrb_ary_new_from_values(mrb, argc, argv);
- stack_extend(mrb, ci->nregs);
+ stack_extend(mrb, ci->nregs+2);
mrb->c->stack[1] = args;
ci->argc = -1;
argc = 1;
