ports/68281: add SPF support for milter-greylist

[Cyril Guibourg]

Hajimu UMEMOTO <ume at freebsd.org> writes:

>  Oops, I didn't notice this issue.  The recent 5-CURRENT's resolver is
>  thread_safe.  But, 4-STABLE's one is not.  How about adding attached
>  patch for now?  It does giant locking around SPF call.

Imho:

I am afraid it would create problems with loaded MTAs. Imho the best way
it to modify the bind9 port in order to get the thread-safe libbind and link
with it. I am not sure but we may have to figure out if, then, libspf_alt
would be compiled with the right ISC includes. I don't know whether this point
is a strong requirement or not.

I must admit that I still do not have glanced at this.

Regards.