The foo_st names don't appear in OpenSSL public API documentation. The
FOO typedefs are more common. This header was already referencing
SSL_CTX via <openssl/ssl.h>. There is a comment about avoiding
<openssl/x509v3.h>, but OpenSSL actually declares all the typedefs in
<openssl/ossl_typ.h>, which is already included by <openssl/ssl.h> (and
every other OpenSSL header), so just use that. Though I've included it
just to be explicit.
(I'm also fairly sure including <openssl/ssl.h> already triggers the
Schannel conflicts anyway. The comment was probably just out of date.)
Closes#12439
56791f3e23