bind "ALLOW_FILTER_AAAA_ON_V4" changed to "ALLOW_FILTER_AAAA"

["John D. Baker" <jdbaker%mylinuxisp.com@localhost>]

Back at the beginning of April, "src/external/bsd/bind/Makefile.inc"
r1.20 enabled support for the "filter-aaaa-on-v4" option.

While I used a similar local modification successfully on netbsd-6, I've
recently started migrating to NetBSD-7 where support for that option
should now be available by default.

Although built starting with a clean (nonexistent) OBJDIR/DESTDIR, the
resulting 'named' executable claims that "filter-aaaa-on-v4" was not
enabled at compile time and fails to start.

It appears that the version of "bind" in NetBSD-7 and HEAD has changed
the enabling macro name to simply "ALLOW_FILTER_AAAA".

As such "src/external/bsd/bind/Makefile.inc" should be updated to match
and pulled up to netbsd-7.

Thanks.

-- 
|/"\ John D. Baker, KN5UKS               NetBSD     Darwin/MacOS X
|\ / jdbaker[snail]mylinuxisp[flyspeck]com    OpenBSD            FreeBSD
| X  No HTML/proprietary data in email.   BSD just sits there and works!
|/ \ GPGkeyID:  D703 4A7E 479F 63F8 D3F4  BD99 9572 8F23 E4AD 1645