This adds the standard OpenSSL api to get a pointer to the SSL struct's X509_VERIFY_PARAM. We need this for the OpenSSL api to set the peer hostname introduced in the next patch.
This wrapper has come from Espressif's esp-idf https://github.com/espressif/esp-idf/tree/master/components/openssl under Apache 2.0, at or around commit 3e4627479b6fff6b652de6d2f0302101e51ee5c2