Log Message:
net/bind914: Fix build under NetBSD-current

This package automatically enabled the "blacklist" option under recent
enough versions of NetBSD. However in NetBSD-current the "blacklist"
library has been replaced by the "blocklist" library which BIND currently
doesn't support. And as result the build failed with the default option
because the "blacklist" could not be found.

Change the option check to only enable this option under NetBSD if the
"blacklist" header file can be found. This fixes the build under
NetBSD-current with the default options.

The correct long term fixed would be:
* Wait for a BIND version which supports "blocklist" instead of \ 
"blacklist"
* Add "blocklist" as a package in "pkgsrc" with an \ 
appropriate "builtin.mk"