The version of curl shipped with the Wii U includes a few extra options, mostly for configuring the SSL implementation.
These options are passed to curl_easy_setopt.
The NSSLContext obtained from calling NSSLCreateContext. Required for SSL connections.
nn_ec.rpl sets this to 3.
nn_ec.rpl sets this to 0, doesn't appear to be handled in the actual library itself (returns an error?)