buildroot

bind: bump version to 9.11.0

- With the release of BIND 9.11.0, ISC is changing the open source
  license for BIND from the ISC license to the Mozilla Public License
  (MPL 2.0). See release notes:
  http://ftp.isc.org/isc/bind9/9.11.0/RELEASE-NOTES-bind-9.11.0.html

- Explicitly enable/disable zlib support, otherwise the configure script
  will fail like this:

  checking for zlib library... yes
  checking for library containing deflate... no
  configure: error: found zlib include but not library.

Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>