Rewrite the stack

src/main.c

@@ -18,14 +18,15 @@ int main(int argc, const char **argv) {
     fclose(in);
     lisp_init();
     REGISTER_GLOBAL_FUNCTION(print);
-    push_stack_frame(Qnil, Qnil, Qnil);
+    push_local_reference_frame();
+    StackFrame *toplevel = LISP_STACK_REF();
     ReadStream s;
     read_stream_init(&s, src, src_len);
     LispVal *r;
     while ((r = read(&s))) {
         Feval(r, Qnil);
     }
-    pop_stack_frame();
+    unwind_to(toplevel);
     lisp_shutdown();
     free(src);
     return 0;