> extension [-Werror,-Wgcc-compat]
> __rte_internal
> ^

Which clang version is this?

Clang 10, 11, 12 and 13.

Perhaps the allow internal API could use a different attribute that
could work in both cases?

I've realised I've made a small error. It is not -Wall that includes this particular check, but -Wpendantic. I'll update the commit message.

However I can't find an attribute that is cross platform. There is the #error directive, but it does not work as an attribute. I've also tried adding `#if __clang__` around the macro as well, but the warning still gets triggered by clang.

If there are any other options that I've missed, let me know and I can try them out.

Mike.