We should answer the following questions in our documentation.

In order to build an application that makes SSL connections to the server:

• Do users have to explicitly request SSL support when building the C driver? (it depends on whether they have prereqs installed?)
• Do users have to explicitly request SSL support when building the C++ driver? (no, defaults to on)
• Do users have to specify "ssl=true" in their connection URI, or ssl_opts() in their client options? (yes)

The C driver documents some of the above in its "Advanced Connections" page: http://mongoc.org/libmongoc/1.6.1/advanced-connections.html#connecting-to-a-server-over-ssl

Where possible, we should also detect whether the user has skipped any of the above steps, and issue a readable diagnostic or error (e.g. when building an SSL C++ driver against a non-SSL C driver).