Support linking against system OpenSSL (#218)

PACKAGING.md

@@ -0,0 +1,27 @@
+# Notes For Package Maintainers
+
+## Linking Against System Packages
+
+The default Cargo features for __iamb__ will bundle SQLite and use [rustls] for
+TLS. Package maintainers may want to link against the system's native SQLite
+and TLS libraries instead. To do so, you'll want to build without the default
+features and specify that it should build with `native-tls`:
+
+```
+% cargo build --release --no-default-features --features=native-tls
+```
+
+## Enabling LTO
+
+Enabling LTO can result in smaller binaries. There is a separate profile to
+enable it when building:
+
+```
+% cargo build --profile release-lto
+```
+
+Note that this [can fail][ring-lto] in some build environments if both Clang
+and GCC are present.
+
+[ring-lto]: https://github.com/briansmith/ring/issues/1444
+[rustls]: https://crates.io/crates/rustls