Adding file descriptor attribute(s) to gcc and glibc

[Paul Eggert]

On 7/14/22 08:22, David Malcolm via Libc-alpha wrote:
> The analyzer now attempts to track both file descriptors and stdio
> streams, so we probably need to special-case fdopen

You probably also need to special-case fileno, which goes the opposite 
direction.

If you're handling DIR *, fdopendir and dirfd would need similar treatment.