This crate is an unsafe wrapper for [libunbound](https://unbound.nlnetlabs.nl)
from [NLnet Labs](https://nlnetlabs.nl). libunbound is an implementation of a
DNS resolver, including cache and DNSSEC validation.

### Building

libunbound depends on OpenSSL which this crate relies on
[rust-openssl](https://github.com/sfackler/rust-openssl) to provide.

The following environment variables influence the build process:

* `UNBOUND_STATIC`- If specified libunbound will be linked statically.
* `UNBOUND_DIR` - Directory in which libunbound's `include` and `lib` folders may be found.