Check more `MRB_ARGS_NONE()`

The `__id__` method implemented in the C function has `MRB_ARGS_NONE()` specified, but it is also effective in the following cases.

```ruby
p nil.__id__ opts: 1 rescue p :a
p nil.method(:__id__).call 1 rescue p :b
p nil.method(:__id__).call opts: 1 rescue p :c
p nil.method(:__id__).to_proc.call 1 rescue p :d
p nil.method(:__id__).to_proc.call opts: 1 rescue p :e
p nil.method(:__id__).unbind.bind_call nil, 1 rescue p :f
p nil.method(:__id__).unbind.bind_call nil, opts: 1 rescue p :g
p nil.__send__ :__id__, 1 rescue p :h
p nil.__send__ :__id__, opts: 1 rescue p :i
```

After applying this patch, all items will output symbols in the same way as CRuby.

For this purpose, add `MRB_PROC_NOARG` to `struct RProc::flags`.

1 files changed, 2 insertions, 0 deletions

diff --git a/include/mruby/proc.h b/include/mruby/proc.h
index 31f40d379..1ba485783 100644
--- a/include/mruby/proc.h
+++ b/include/mruby/proc.h
@@ -83,6 +83,8 @@ struct RProc {
 } while (0)
 #define MRB_PROC_SCOPE 2048
 #define MRB_PROC_SCOPE_P(p) (((p)->flags & MRB_PROC_SCOPE) != 0)
+#define MRB_PROC_NOARG 4096 /* for MRB_PROC_CFUNC_FL, it would be something like MRB_ARGS_NONE() or MRB_METHOD_NOARG_FL */
+#define MRB_PROC_NOARG_P(p) (((p)->flags & MRB_PROC_NOARG) != 0)
 
 #define mrb_proc_ptr(v)    ((struct RProc*)(mrb_ptr(v)))