The latest version of libstdc++ in Arch Linux at this point (13.1.1)
pulls in the following code via `#iterator <iterator>` when
`-std=gnu++2b` is used:
```
template<forward_iterator _It>
struct __basic_const_iterator_iter_cat<_It>
{ using iterator_category =
iterator_traits<_It>::iterator_category; };
```
The latest version of Clang in Arch Linux at this point (15.0.7)
complains about a missing `typename` here. To avoid this error
from preventing the build, this changes enables error resilience
for the reflection generation to turn this error into a warning.
Martchus
cf6b90407e